Abstract: Apparatus and a method for its use in cleaning comminuted thermoplastic material for reuse in manufacture of molded plastic products. Batches of plastic including adherent label materials and adhesives are agitated by a rotor until frictionally heated to a predetermined temperature. A flow of air is used to carry away loosened labels and adhesives. A small amount of water is introduced as a spray to dissolve adhesives and soften remaining label materials further, while loosened pieces continue to be removed in a stream of air. Thereafter, remaining adherent particles are removed in an aspirator providing a multi-stage cascade through counter-currents of air, and the particle-carrying air is then cleaned in a cyclone separator.

Abstract: An erasable optical data storage medium including a substrate and a dual layer of a first material and a second material on the substrate. The dual layer is susceptible to expansion and contraction, to writing data thermally, to erasing data thermally and mechanically, and to reading data optically, the first material and the second material, respectively, being bonded together and remaining in the same physical state upon the expansion and relaxation of the dual layer. Methods and apparatus are also disclosed for recording data bits on the medium.