There are provided processes for recycling waste such as polystyrene thermoplastic polymer waste and/or polystyrene thermoplastic copolymer waste as well as recycled polystyrene thermoplastic polymer and/or recycled thermoplastic copolymer that may, for example, be obtained from such processes. The processes can comprise dissolving the waste in cymene, xylene or ethylbenzene or a suitable solvent, to obtain a mixture followed by heating the mixture under acidic conditions and then optionally neutral conditions in the presence of a reducing agent then cooling to obtain a supernatant comprising polystyrene thermoplastic polymer and/or polystyrene thermoplastic copolymer and a solid waste residue. The supernatant can optionally be treated with a filtration aid, then the supernatant can be contacted with a hydrocarbon polystyrene non-solvent under conditions to obtain precipitated polystyrene thermoplastic polymer and/or precipitated polystyrene thermoplastic copolymer which can be washed with additional hydrocarbon polystyrene non-solvent, and optionally dried and formed into polystyrene thermoplastic polymer pellets and/or polystyrene thermoplastic copolymer pellets.