APPARATUS, METHOD AND SYSTEM FOR RECYCLING WASTE EXPANDED PLASTIC PRODUCT COMPRISING A CONTAMINANT BACKGROUND [0001] Expanded plastics, such as EPS (Expanded Polystyrene) and GPPS (General Purpose Polystyrene) are often used as filler, insulation, soundproofing, packing, and packaging materials for marine, fishery, automotive, electronics, hospital, food service, and construction applications. Due to their size, waste expanded plastics can take up significant space in storage or landfills. Expanded plastics can be reused, however, the lightweight and lost cost character of these materials presents a challenge for cost-effective transportation and handling of discarded or waste expanded plastic. BRIEF DESCRIPTION OF DRAWINGS [0002] This disclosure includes various examples that may be more completely understood in connection with the accompanying drawings, in which: [0003] FIG.1 describes an example apparatus for discharging waste expanded plastic, consistent with the present disclosure. [0004] FIG.2 describes an example apparatus for discharging waste expanded plastic having a collection bin coupled to the separation chamber, consistent with the present disclosure. [0005] FIG.3 describes an example method for discharging waste expanded plastic, consistent with the present disclosure. [0006] FIG.4 is describes an example system for discharging and densifying a waste expanded plastic, consistent with the present disclosure. [0007] FIG. 5 is a schematic representation of an example system for discharging and densifying a waste expanded plastic product having a solid surface contaminant, consistent with the present disclosure. [0008] The various examples discussed herein are amenable to modifications and alternative forms. While aspects of these modifications have been shown by way of example in the drawings, and described in detail below, the intention is not to limit the disclosure to the particular examples described. Rather, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure, including aspects defined in the claims. DETAILED DESCRIPTION [0009] In the following detailed description, reference is made to the accompanying drawings which form a part hereof. These illustrations provide examples by which the disclosure may be practiced. Still other examples may be utilized; and structural or logical changes may be made without departing from the scope of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims. Features of the various examples described herein may be combined, in part or whole, with each other, unless specifically noted otherwise. [0010] The present disclosure describes discharging waste expanded plastics. “Expanded plastic” refers to or includes plastic material in the form of foam with a closed-cell or open-cell structure, and which may be flexible or rigid. Recycling or disposal of expanded plastic may include removing some or all of the air trapped in the foam, thereby reducing the volume of the expanded plastic. The smaller size of the expanded plastic facilitates storage and transportation. Dissolution with solvents can be used for volume reduction, however, the dissolved plastic is often transported to another facility as a liquid for recycling. The volume of expanded plastic can be reduced by hot melt processes involving heating the material to 200 °C or greater. In order to have an adequate balance between the energy and environmental inputs for recycling and reuse of expended plastics, recycling programs for expanded plastics would benefit from improved efficiency and lower energy consumption. [0011] Discharging waste expanded plastic in accordance with the present disclosure may improve the efficiency of volume reduction, improve the cost- effectiveness of recycle and reuse programs, reduce the environmental impact of transporting and recycling waste expanded plastic, improve the quality of the waste expanded plastic for recycle and reuse, or any combination thereof. For example, discharging waste expanded plastics, as described herein, may reduce cost inputs associated with use of solvents, heat, and equipment repair following damage caused by solid surface contaminants. Discharging waste expanded plastics using the apparatus, methods, and systems of the present disclosure may achieve improved high-density compression. [0012] FIG. 1 describes an example apparatus 100 for discharging waste expanded plastic, consistent with the present disclosure. The term “example” as used throughout this application is by way of illustration, and not limitation. As used herein, “waste expanded plastic product” refers to or includes a discarded article containing any type of expanded plastic. For example, the expanded plastic may be or may include polystyrene, expanded polyethylene, expanded polypropylene, expanded polystyrene (EPS), general purpose polystyrene (GPPS), expanded polyvinyl chloride, expanded polyamide or plastic material in the form of foam with a closed-cell or open-cell structure, and which may be flexible or rigid. In some cases, the waste expanded plastic product includes polystyrene, such as EP and/or GPPS (also referred to herein as “EPS/GPPS”). The waste expanded plastic product may include manufacturing waste, aquaculture waste, marine waste, cushioning material, automotive bumpers and interior passenger safety components, fish boxes, insulation waste, construction waste, coolers, to-go boxes and other food packaging waste, EPS concrete, and mixtures of products. [0013] Apparatus 100, which is not illustrated to scale, may discharge a waste expanded plastic product (not shown), such as discarded EPS/GPPS, for various types of recycling and reuse. [0014] In the example illustrated in FIG.1, apparatus 100 includes a separation device 102 and a fragmenting device 104. As used herein, a “separation device” refers to or includes any device or combination of devices for separating a surface solid contaminant from a waste expanded plastic product. The device may be operated by sieving, screening, sifting, or by using gas currents, or separating by other dry methods applicable to articles of waste expanded plastic. Non-limiting examples of a separation device includes a dry density separator, an air knife separator, a bag-type mechanical vibrating machine, an air drum separator, a bag- type high-pressure blower, a counter blowing rotary collector, a pulsed jet bag type collector, a filtering cylinder type separator, or a combination thereof. As used herein, a “fragmenting device” refers to or includes any device or combination of devices for reducing the size of the expanded plastic, such as by crushing, pulverizing, or disintegrating. The fragmenting device can be electric or hydraulic. Non-limiting examples include devices for disintegrating by knives or other cutting or tearing members to chop material into fragments, and devices for crushing, pulverizing, or disintegrating by disc mills, roller mills, gyratory or cone crushers, reciprocating members, and combinations thereof. Fragmentation device 104 may include a crusher, grinder, granulator, shredder, knife cutter, rotary cutter, or a combination of these devices. Fragmenting device 104 may be selected for the composition of the product to be subjected to size reduction, or selected based on the size, shape, or thickness of the product. The type of device for fragmenting device 104 may be based on the downstream use of the discharged waste expanded plastic product. Fragmenting device 104 may include a device for reducing the size of the waste expanded plastic product to about 3 to about 50 mm along a longest dimension. In one example, fragmenting device 104 includes a grinder or shredder for discharging fragments of expanded plastic for use. For example, a grinder or shredder for reducing a waste product containing EPS to individual EPS beads of about 3-5 mm may be included in fragmenting device 104. Apparatus 100, separation device 102, and fragmentation device 104 may be dimensioned to accommodate the size and shape of the waste expanded plastic product. Waste expanded plastics that have been discharged by apparatus 100 may be used, such as, for example, filler for consumer items, lightweight concrete aggregate, backfilling material, etc. Apparatus 100 may discharge waste expanded plastic products for further processing, such as for volume reduction. [0015] As shown, in FIG. 1, separation device 102 includes a separation chamber 106, with a feeding inlet 107; an air movement device 108; and a discharge outlet 110. A “separation chamber” as used herein refers to or includes a space, cavity, or compartment that is a least partially enclosed, into which the waste expanded plastic product, may be housed during separation. As used herein, “feeding inlet” refers to or includes an opening to direct the waste expanded plastic product into the separation chamber. As used herein, “air movement device” refers to or includes any device for enhancing air flow through the separation chamber. Air movement device 108 may operate by blowing, generating, or otherwise producing a stream of air within or through separation chamber 106. The stream of air may be a horizontal, vertical, or vortex air stream. Non-limiting examples of air movement device 108 include a blower, fan, vacuum, compressor, pneumatic conveyer, or the like. As used herein, “discharge outlet” refers or includes an opening for directing the waste expanded plastic product in separation chamber 106 to the exterior environment of separation chamber 106, or the exterior environment of separation device 104. [0016] Separation device 102 for separating a surface solid contaminant from a waste expanded plastic product, may clean the surface of the waste expanded plastic product. The type of solid surface contaminant on a waste expanded plastic product will vary depending on the original use and/or storage conditions of the product. Non-limiting examples of solids that may contaminate a surface of waste expanded plastic include dense plastics, glass, concrete, seaweed, algae, mud, soil, sand, shells, stones, food waste, and salt. [0017] In operation of apparatus 100, separation device 102 receives the waste expanded plastic product for entraining in the enhanced air flow generated by air movement device 108 within separation chamber 106 between feeding inlet 107 and discharge outlet 110. As used herein, “entraining” refers to or includes drawing in, carrying on, or transporting of a solid by the flow of a gas current, such as an air stream. The solid surface contaminant is separated from the surface of the entrained waste expanded plastic product. Removal may avoid damage caused by or associated with contact with a solid surface contaminant on a waste expanded plastic product which has not been processed using separation device 102. The separated solid is selectively removed from the air stream by gravity upstream of discharge outlet 110. As used herein, “selectively removed” refers to and includes the removal of selected elements, such as a solid contaminant present on the surface of a waste expanded plastic product. Waste expanded plastic products discharged from separation device 102 may be fed into fragmenting device 104. [0018] Fragmenting device 104 comprises an outlet 112 for separating liquid contaminants in or on the waste expanded plastic product. Outlet 112 may be or may include an opening, hole, vent, drain, pipe or other passage through which a liquid contaminant may flow out of the fragmenting device 104. As used herein, “liquid contaminant” refers to or includes a liquid introduced to the expanded plastic product after manufacture, during use, or during storage. Non-limiting examples of liquid contaminants include seawater, water, food and industrial oils, or combinations thereof. [0019] FIG. 2 describes an example apparatus 200 for discharging waste expanded plastic, consistent with the present disclosure. Apparatus 200, which is not illustrated to scale, may discharge a waste expanded plastic product (not shown), such as a product described above, for various types of recycling and reuse. [0020] In the example illustrated in FIG.2, apparatus 200 includes a separation device 202 and a fragmentation device 214. Separation device 202 may be or may include a separation device as described for apparatus 100. Fragmentation device 214 may be or may include a fragmentation device as described for apparatus 100. Fragments of waste expanded plastic products discharged by apparatus 200 may be used as, for example, filler for consumer items, lightweight concrete aggregate, backfilling material, etc., and/or further processed by volume reduction, densification, or other process for reuse or recycle expanded plastic. [0021] The separation device 202 includes: a separation chamber 204 with a feeding inlet 208; an air movement device 206; and a discharge outlet 210. Separation chamber 204, feeding inlet 208, air movement device 206, and/or discharge outlet 210 may be or may include a separation chamber, feeding inlet, air movement device, and/or discharge outlet as described for apparatus 100, respectively. [0022] In operation of apparatus 200, the waste expanded plastic product is entrained within separation chamber 204 between the feeding inlet 208 and discharge outlet 210. Air movement device 206 may be arranged to supply and direct the stream of air through separation chamber 204. The air movement device can be positioned adjacent to or within separation chamber 204 to blow, generate, or otherwise create a stream of air through separation chamber 204 between feeding inlet 208 and discharge outlet 210. To facilitate separation of the surface solid contaminant from the waste expanded plastic product, air movement device 206 can be variable frequency and/or have dampeners to adjust the flow of air through separation chamber 204. Separation device 202 may include a dry density separator, an air knife separator, a bag-type mechanical vibrating machine, an air drum separator, a bag-type high-pressure blower, a counter blowing rotary collector, a pulsed jet bag type collector, a filtering cylinder type separator, or a combination thereof. [0023] In the example illustrated in FIG.2, separation device 202 includes a collection bin 212 coupled to separation chamber 204. As used herein, “collection bin” refers to or includes a receptacle for storing solid contaminants separated from the waste expanded plastic product. The solid contaminants that are separated from the surface of the waste expanded plastic product may fall or drop into collection bin 212. The collection bin may be positioned within or under the separation chamber 204 to passively collect the solid contaminants that are separated from the entrained expanded plastic product by gravity. Collection bin 212 may be removable or may include an access panel to permit emptying (not shown). [0024] In the example illustrated in FIG. 2, Fragmentation device 214 is positioned to receive the waste expanded plastic product discharged from separation device 202. Discharge outlet 210 may be operably connected to fragmentation device 214. In one example, discharge outlet 210 may be coupled to a conveyor, hopper, feeder, or chute (not shown) for feeding the discharged waste expanded plastic product to the fragmentation device. Fragmentation device 214 may be a top fed device or a forced side feeding device. Fragmentation device 214 may have a suitably sized inlet for receiving the waste expanded plastic product. Fragmentation device 214 includes discharge 218 to allow fragments of size reduced expanded plastic to flow out of the device. Discharge 218 may be smaller than discharge outlet 210. [0025] During operation of fragmentation device 214, a liquid contaminant present in or on the waste expanded plastic product may be removed from the waste expanded plastic product. The liquid contaminant may fall from the surface or be extracted from within the waste expanded plastic product during size reduction. The liquid contaminant may flow out of the device via outlet 216. Outlet 216 may be or may include an outlet as described for apparatus 100. Outlet 216 may be operably connected to device for removing a liquid, such as a dryer, suction fan, or a vacuum pump and/or fluidically connected to a vessel (not shown) for collection and disposal of a liquid. A vessel for connection to outlet 216 may be any vessel suitable for holding water, seawater, food and industrial oils, or other liquid residues that may be present on a waste expanded plastic product. [0026] FIG. 3 describes an example method 300 for discharging waste expanded plastics, consistent with the present disclosure. At 302 of method 300, a waste expanded plastic, such as a waste expanded product described with respect to apparatus 100 or 200 with surface contamination is entrained in an air stream to produce cleaned expanded plastic. As discussed above, “entraining” refers or includes drawing in, carrying on, or transporting of the waste expanded plastic using the flow of a gas current, such as an air stream. The air stream for entraining can be a horizontal, vertical, or vortex air stream, or any air stream whereby solid contaminants are separated from the surface of the waste expanded plastic. By separating the surface solid contaminants from the waste expanded plastic at 302, method 300 produces a cleaned expanded plastic. As used herein, “cleaned” refers to a waste expanded plastic product that has been treated to remove, at least some or all of the solids that may contaminate the surface of a waste expanded plastic, such as the solid contaminants described above. The type of solid surface contaminant on the waste expanded plastic will vary depending on the original use of the expanded plastic. Non-limiting examples of solid surface contaminants may include dense plastics, glass, concrete, seaweed, algae, mud, soil, sand, shells, stones, food waste, and salt. [0027] Method 300 may be practiced with any type of expanded plastic or combination thereof. As discussed above, the term “expanded plastic” refers to or includes plastic material in the form of foam with a closed-cell or open-cell structure. The foam of an expanded plastic may be flexible or rigid. The expanded plastic may include, for example, polystyrene, GPPS, expanded polyethylene, expanded polypropylene, EPS, expanded polyvinyl chloride, expanded polyamide, or combinations of these. In some examples, the expanded plastic includes polystyrene, such as EPS/GPPS. Sources of waste expanded plastic may include, but are not limited to, manufacturing waste, aquaculture waste, marine waste, packaging waste, such as cushioning material, fish boxes, coolers, to-go boxes and other food packaging waste, automotive bumpers and interior passenger safety components, insulation waste including heat and/or sound insulation panels, construction waste such as structural products including composite panels, and EPS concrete. Method 300 may be practiced with a waste expanded plastic that has not been subjected to a pre-treatment, such as preliminary or preparatory cleaning or size reduction. For example, at 302, method 300 may include entraining a waste expanded plastic that has not been cleaned, such as a waste expanded plastic that has not been washed, wiped, or brushed to remove a surface contaminant. [0028] At 302, method 300 may include generating an air stream to entrain the waste expanded plastic. In one example, method 300 includes entraining the waste expanded plastic in an air stream generated by a bag-type mechanical vibrating machine, a bag-type high-pressure blower, a counter blowing rotary machine, a filtering cylinder type separator, or a combination thereof. The air stream may carry or transport the waste expanded plastic over a gap. As used herein, “gap” refers to or includes an empty space or opening between two structural elements, such as between an entry and an exit of a housing, chamber, or container holding the entrained waste expanded plastic. For example, the solid contaminant may be separated from the waste expanded plastic by falling, dropping, or passing, due to gravity, downward through the stream of air and into the gap. The surface contaminated expanded plastic may contact/interact with the air stream. A solid contaminant may be dislodged by air or by the movement of the expanded plastic in the air stream. The dislodged solid contaminant, being heavier than the waste expanded plastic, may not be supported by the air stream. The waste expanded plastic is carried by the air stream. [0029] At 304 of method 300, the cleaned expanded plastic is fragmented. “Fragmented” as used herein refers to pieces of expanded plastic formed as a result of a stress on the cleaned waste expanded plastic. As used herein “stress” refers to or includes a pressure or tension exerted on the expanded plastic. Examples of stress that may cause fragmenting include compressive stresses, such as crushing; shear stresses; surface pressures, such as abrasion, grinding, and/or impact; bending stresses; and combinations thereof. The cleaned expanded plastic may be fragmented by feeding the cleaned expanded plastic into a fragmenting device, such as a shredder, grinder, granulator, cutter, or crusher, or a fragmentation device such as fragmentation device 104 or 214. Feeding may include gravitational or forced feeding. The cleaned expanded plastic may be fragmented to achieve a specific size reduction ratio. “Size reduction ratio” as used herein refers to the quotient IS/FS of the average initial size (IS) of the waste expanded plastic and the average size of the fragmented product (FS). In an example, the fragmented expanded plastic has a size of about 5-50 mm along the longest dimension. [0030] In one example, at 304, method 300 includes removing a liquid contaminant on or in the cleaned expanded plastic. While the cleaned expanded plastic is being fragmented, liquid contaminants on the surface and/or moisture within the expanded plastic may be drawn or drained from the fragments. Example liquid contaminants include, but are not limited to, water, seawater, food and industrial oils, and other liquid residues which may contaminate waste expanded plastic during or after use. [0031] Drawing the liquid contaminants from the expanded plastic may be performed under a reduced pressure. For example, method 300 may include using a size reduction device operated under reduced pressure conditions and/or reducing air pressure within the size reduction device, or a chamber therein. A size reduction device may be a fragmentation device as described above for apparatus 100 or 200. The reduced pressure conditions may include a range of about 0.1 to about 1 ATM, or less than 1 ATM, which may be maintained for any period of time during which the cleaned expanded plastic is fragmented, such as the entire period, or an interval thereof. In some cases, reducing air pressure may include connecting a depressurizing device to the size reduction device. The depressurizing device may include a vacuum pump, a fan, a blower, or other device producing low pressure air. [0032] At 306, method 300 includes compressing the fragmented expanded plastic. As used herein, “compressing” refers to or includes any mechanical method of reducing the volume of the fragmented expanded plastic. Mechanical volume reduction may include crunching, crushing, or squeezing the fragments of expanded plastic or pressing the fragments of expanded plastic together, and combinations thereof. During compression, some or substantially all the air within the foam is removed from the fragmented expanded plastic. The expanded plastic may be compressed to any compression ratio. The compression ratio is based on the initial volume of the fragmented expanded plastic and the final volume of the compressed product. In one example, the fragmented expanded plastic is compressed to a compression ratio that reduces the cost inputs of transportation or storage of the waste expanded plastic, such as up to about 50:1. The expanded plastic may be compressed to a compression ratio of at least 25:1, 30:1, 35:1, 40:1, 45:1 or up to about 50:1. Compressing may result in moisture on or in the expanded plastic being released. In one example, at 306, method 300 may include separating the moisture released from the fragmented expanded plastic during compression, such as by draining or otherwise allowing the moisture to collect and flow away from the fragments. [0033] At 308, method 300 includes extruding the compressed expanded plastic. As used herein, “extruding” refers to or includes shaping the compressed expanded plastic, such as into bricks, logs, planks, cylinders, or any other shape suitable for storage or transportation. Extruding may increase the compression ratio and may further reduce the volume of the compressed expanded plastic. [0034] For illustration purposes, method 300 is described in a specific non- limiting example practiced using a marine waste foam buoy comprising EPS/GPPS. Marine waste may be contaminated with seawater and sand. The foam buoy may be entrained in an air stream. The sand and salt may be separated from the entrained foam buoy in the air stream producing a cleaned foam buoy. The cleaned foam buoy may be fragmented, and the seawater may be separated from the cleaned foam buoy to produce fragments of the foam buoy. The fragments may be compressed and the compressed fragments may be extruded into a compact shape. The volume of the extruded material improves the cost-effectiveness of storage and/or transportation for recycle or reuse of the EPS/GPPS. Separation of sand, salt, and/or seawater from the foam buoy reduces weight of the extruded material, protects equipment, and improves the compression ratio of the extruded product, as compared with marine waste that has not been entrained in an air stream prior to fragmentation. [0035] An example system for discharging waste expanded plastic is described in FIG. 4. System 400, which is not illustrated to scale, includes a mechanical processing unit 402 and a volume reduction unit 404. System 400 may improve the efficiency of storing or transporting the waste expanded plastic, as well as densify the waste expanded plastic to prevent it from being caught by wind currents and entering or re-entering the natural environment. [0036] Mechanical processing unit 402 includes a solids separator 403 to separate solid foreign matter from a waste product comprising an expanded plastic (not shown). As used herein, “mechanical processing” refers to or includes machines or machinery for subjecting waste expanded plastic to one or more physical processes. As used herein, “solids separator” refers to or includes any type of apparatus or device for separating solid foreign matter on a surface of the waste product. Solids separator 403 may operate by sieving, screening, sifting or by using gas currents, or separating by other dry methods applicable to waste products including expanded plastic, and combinations thereof. As used herein “solid foreign matter” refers to or includes solids that were introduced before or during the manufacturing process of the product, during use of the product, or after the product has been discarded. For example, solid foreign matter may include dense plastic introduced during manufacture of an automobile bumper. The “waste product” can be any article that includes an expanded plastic. For example, the waste product may be manufacturing waste, aquaculture waste, marine waste, cushioning material, automotive bumpers and interior passenger safety components, fish boxes, insulation waste, construction waste, coolers, to-go boxes and other food packaging waste, EPS concrete, and mixtures of materials containing expanded plastic. The expanded plastic may be flexible or rigid, and may include, for example, polystyrene, GPPS, expanded polyethylene, expanded polypropylene, EPS, expanded polyvinyl chloride, expanded polyamide, or combinations of these. In some examples, the expanded plastic includes polystyrene, such as EPS/GPPS, as described above. As used herein, “volume reduction unit” refers to or includes one or more devices or apparatus for reducing the amount of space that the waste product occupies and/or to put the waste product into a form suitable for storage or transport. [0037] As shown in FIG.4, solids separator 403 includes a container 405 for the waste product and an agitating mechanism 407. The container for the waste product is dimensioned to hold the waste product during agitation and to allow the solid foreign matter to be separated from the waste product. As used herein, “agitating mechanism” includes any device or apparatus for putting the waste product into motion. For example, agitating mechanism 407 may include a motor, shaker, sifter, suction fan, blower, or a combination thereof. The intensity and speed of the motion may vary for separation of the solid foreign matter from the waste product. [0038] Mechanical processing unit 402 includes a liquid separator 409. As used herein, “liquid separator” refers to or includes any device of apparatus for removing liquid from a waste product comprising expanded plastic. Liquid separator 409 may operate by crushing, squeezing, pulverizing, pressing, or disintegrating the waste product, and/or by draining, drying, drawing off, or conveying liquid away from the waste product. Liquid separator 409 includes an inlet 413 at a top portion of housing 411, a liquid releasing mechanism 415, and an outlet 417 at a bottom portion. As used herein, “liquid releasing mechanism” refers to or includes any device or apparatus for allowing liquid within or on the waste product to be released from the expanded plastic. Non-limiting examples of a liquid releasing mechanism include a crusher, grinder, granulator, shredder, knife cutter, rotary cutter, or a combination of these devices. Inlet 413 is dimensioned and/or positioned to receive the expanded plastic from solids separator 403. Outlet 417 has a smaller dimension than inlet 413. Volume reduction unit 404 is operably connected to outlet 417 and includes a cold compression device 419. As used herein, “cold compression” refers to or includes machines that do not use heat during the compaction process, such as screw-type densifiers, hydraulic pressure foam densifiers, or other non-thermal densifiers. The term “non-thermal” refers to an operation temperature below 200 °C. [0039] In one example, liquid releasing mechanism 415 includes a crusher, shredder, or chopper for disintegrating the expanded plastic. [0040] In one example, liquid separator 409 includes a drain, vacuum pump or suction fan. [0041] In one example, agitating mechanism 407 includes a bag-type mechanical vibrating machine, bag-type high-pressure blower, counter blowing rotary machine, and filtering cylinder type separator, or a combination thereof. [0042] In one example, compression device 419 comprises an extruder. [0043] Another example system for discharging waste expanded plastic is described in FIG. 5. System 500, which is not illustrated to scale, includes a mechanical processing unit 502 and a volume reduction unit 504. Mechanical processing unit 502 includes a solids separator 502-1 and a liquid separator 502-2 comprising an inlet 519 at a top portion of housing 517 to receive the expanded plastic from the solids separator 502-1 and a liquid releasing mechanism 518. Example expanded plastic product 503 comprising solid foreign matter 505 may be fed into container 507 at inlet 509 by any means, including gravity or force feeding. [0044] Solids separator 502-1 includes an agitating mechanism 511. Container 507 is dimensioned for holding the waste expanded plastic product 503 while it is being agitated. Agitation may dislodge solid foreign matter 505. Agitating mechanism 511 can be an air separator to entrain the received waste expanded plastic product 503 within an air stream, such as an air density separator, that is capable of suspending the waste expanded plastic product to be cleaned in an air stream. Non- limiting examples include the examples described above, such as a bag-type mechanical vibrating machine, bag-type high-pressure blower, counter blowing rotary machine, and filtering cylinder type separator. Combinations of these are also contemplated. Container 507 includes outlet 533 to discharge cleaned expanded plastic product 513. [0045] Solids separator 502-1 includes collection bin 508 for collecting solid foreign matter 505 that has been dislodged during operation. Collection bin 508 is positioned below container 507 to collect solid foreign matter that falls, however, other examples are not so limited. Dislodged foreign matter such as dense plastics, concrete, seaweed, algae, mud, soil, sand, shells, stones, food waste, and salt that may contaminate the surface of waste expanded plastic product 503 may fall or drop into collection bin 508. Collection bin 508 may be removable or include an access panel to permit emptying. [0046] Liquids separator 502-2 includes an outlet 527 which has a smaller dimension than inlet 519. As shown, outlet 527 is located at a lower portion of the housing 517 for discharging of expanded plastic that has been cleaned by operation of mechanical processing unit 502; however, embodiments are not so limited and outlet 527 may be located at other positions of liquids separator 502-2. [0047] As shown in FIG.5, housing 517 includes a liquid remover 510. Liquid remover 510 may be or include a drain, or a coupler for a vacuum pump or suction fan for removing liquid contaminants, such as seawater, water, food and industrial oils, or combinations thereof, that may be present in or on the cleaned waste expanded plastic product. [0048] Liquid releasing mechanism 518 may include a fragmenting device that breaks down cleaned waste expanded plastic into progressively smaller pieces, which pieces are shown as larger fragments 521 and smaller fragments 523 and 525 in FIG.5. A suitable fragmenting device may be or may include device for a size- reduction described above. For example, liquid releasing mechanism 518 may include a crusher, shredder, cutter, or chopper for reducing cleaned expanded plastic product 513 into fragments, such as substantially regularly shaped smaller fragments 525 and/or irregularly shaped smaller fragments 523. [0049] Volume reduction unit 504 is operably connected to outlet 527 for receiving expanded plastic free or substantially free of solid and liquid contaminants, as well as expanded plastic that has been fragmented. [0050] Volume reduction unit 504 includes a cold compression device 529. Cold compression minimizes off-gassing from thermal decomposition of expanded plastic, and thereby improves environmental and occupational safety and reduces operational costs. The cold compression device may include a pressure adjuster to adjust the compression ratio according to the characteristics of the expanded plastic. In some cases, the pressure adjuster operates to achieve a compression ratio of at least 25:1, 30:1, 35:1, 40:1, 45:1 or up to about 50:1. Cold compression device 529 may include any device that compacts expanded plastic without applying heat, such as a hydraulic densifier or a screw-type compressor. [0051] Volume reduction unit 504 is fluidically connected to outlet 527. Smaller fragments 525 or 523 are carried by a gas current, such as by air flow, from mechanical processing unit 502 into cold compression device 529 for densification. [0052] Volume reduction unit 504 includes a drain 530 for removing any liquid that may be released from the expanded plastic during compression. In one example, volume reduction unit 504 includes a bag-covered hopper (not shown) that contains and feeds fragments into cold compression device 529. [0053] Volume reduction unit 504 may produce uniformly shaped, compressed, and cleaned expanded plastic 531. For example, volume reduction unit 504 may include an extruder. The extruder may include a blade to cut the extruded material into uniformly sized blocks. [0054] The compressed and/or extruded expanded plastic can be transported or stored for reuse. Because the surface solid and liquid contaminants are removed prior to compression, the compressed material is denser than material that has not been processed using mechanical processing unit 502. The compressed material can be granulated or chopped to form the feed for another process for reuse. * * * * * [0055] Other embodiments of the present disclosure are possible. Although the description above describes specific examples, these should not be construed as limiting the scope of the disclosure, but as merely providing illustrations of some of the examples of this disclosure. Various combinations or sub-combinations of the specific features and aspects of the examples can be made and will fall within the scope of this disclosure. Various features and aspects of the disclosed examples can be combined with or substituted for one another in order to form additional examples. [0056] The foregoing description of various examples of the disclosure have been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise examples, and obviously many modifications and variations are possible in light of the above teaching. The examples, as described above, were chosen and described in order to best explain the principles of the disclosure and its practical application to thereby enable others skilled in the art to best utilize the disclosure.