a method is provided for processing a mixture raw automobile shredder residue , and virgin and / or contaminated synthetic plastic material , e . g ., raw post consumer plastic waste . by means of this method , automobile shredder residue produced by a conventional automobile shredder is formed into a first stream by being ground in a first granulating zone to a reasonable small granular size using conventional equipment . a second stream comprising virgin and / or contaminated synthetic plastics material is ground in a second granulating zones . the two streams are combined to provide a processable mixture . the processable mixture is introduced into a high intensity , mixer . the processable mixtures transformed into a semi - molten discharge stream by the kinetic energy imparted to the processable mixture by the mixer are simultaneously vented from the mixer . the semi - molten mixture emerging from the mixer is then introduced into an extruder or press where it is formed into a mass of desired shape , and cooled . this method allows for the production of useful , shaped masses from two different classes of materials which have been otherwise treated as waste .