These include, but are not limited to, lead salts such as, for example, a sulfate, carbonate, phosphite or phthalate, fillers such as calcium carbonate and calcined clay, flame retardants such as antimony trioxide, adsorbents such as activated charcoal and any badly degraded or crosslinked PVC which also is insoluble in MEK. These insolubles are removed from the solvent mixture by flocculation pro