A process for recycling waste that is thermoplastic polymer waste and/or thermoplastic copolymer waste, the process comprising: - dissolving said thermoplastic polymer waste and/or thermoplastic copolymer waste in a suitable solvent to obtain a mixture of liquid and solids; - heating the mixture under acidic conditions in the presence of a reducing agent, adding a base, heating said mixture under neutral conditions, then cooling the mixture to obtain a supernatant comprising thermoplastic polymer in solution and/or thermoplastic copolymer in solution and a solid waste residue; - separating said supernatant comprising dissolved thermoplastic polymer and/or dissolved thermoplastic copolymer from the solid waste residue; - optionally treating said supernatant with a filtration aid to remove insoluble gels; - contacting said supernatant comprising dissolved thermoplastic polymer and/or dissolved thermoplastic copolymer with a first portion of non-solvent to obtain precipitated thermoplastic polymer and/or precipitated thermoplastic copolymer and a first portion of waste solution; - separating said precipitated thermoplastic polymer and/or precipitated thermoplastic copolymer from said first portion of waste solution; - washing said precipitated thermoplastic polymer and/or precipitated thermoplastic copolymer with a second portion of non-solvent to obtain a washed thermoplastic polymer and/or washed thermoplastic copolymer and a second portion of waste solution; - separating said washed thermoplastic polymer and/or washed thermoplastic copolymer from the second portion of waste solution; - optionally washing said washed thermoplastic polymer and/or washed thermoplastic copolymer with a third portion of non-solvent to obtain a twice-washed thermoplastic polymer and/or twice-washed thermoplastic copolymer and a third portion of waste solution; - optionally separating said twice-washed thermoplastic polymer and/or twice-washed thermoplastic copolymer from said third portion of waste solution; and - optionally drying said washed or twice-washed thermoplastic polymer and/or washed or twice-washed thermoplastic copolymer to obtain dried thermoplastic polymer and/or dried thermoplastic copolymer. - dissolving said thermoplastic polymer waste and/or thermoplastic copolymer waste in a suitable solvent to obtain a mixture of liquid and solids; - heating the mixture under acidic conditions in the presence of a reducing agent, adding a base, heating said mixture under neutral conditions, then cooling the mixture to obtain a supernatant comprising thermoplastic polymer in solution and/or thermoplastic copolymer in solution and a solid waste residue; - separating said supernatant comprising dissolved thermoplastic polymer and/or dissolved thermoplastic copolymer from the solid waste residue; - optionally treating said supernatant with a filtration aid to remove insoluble gels; - contacting said supernatant comprising dissolved thermoplastic polymer and/or dissolved thermoplastic copolymer with a first portion of non-solvent to obtain precipitated thermoplastic polymer and/or precipitated thermoplastic copolymer and a first portion of waste solution; - separating said precipitated thermoplastic polymer and/or precipitated thermoplastic copolymer from said first portion of waste solution; - washing said precipitated thermoplastic polymer and/or precipitated thermoplastic copolymer with a second portion of non-solvent to obtain a washed thermoplastic polymer and/or washed thermoplastic copolymer and a second portion of waste solution; - separating said washed thermoplastic polymer and/or washed thermoplastic copolymer from the second portion of waste solution; - optionally washing said washed thermoplastic polymer and/or washed thermoplastic copolymer with a third portion of non-solvent to obtain a twice-washed thermoplastic polymer and/or twice-washed thermoplastic copolymer and a third portion of waste solution; - optionally separating said twice-washed thermoplastic polymer and/or twice-washed thermoplastic copolymer from said third portion of waste solution; and - optionally drying said washed or twice-washed thermoplastic polymer and/or washed or twice-washed thermoplastic copolymer to obtain dried thermoplastic polymer and/or dried thermoplastic copolymer.