A method of sorting waste material is disclosed herein, the method comprising separating materials in the waste material according to specific gravity, by contacting the waste material with a liquid selected such that a portion of the waste material sinks, to thereby obtain a sorted material containing at least 90 weight percents of material having a specific gravity within a pre-selected range. Further disclosed herein is a method of processing waste material by separating materials in the waste material according to specific gravity as described herein to remove at least a portion of inorganic materials in the waste material, and subjecting a feedstock comprising the obtained sorted material to mixing via shear forces and to heating. Further disclose herein are a polymeric material obtainable by the method of processing waste material, articles-of-manufacturing comprising same, and systems for sorting and processing waste material.