A composition and method purge resin deposits from the inner surfaces of polymer processing machinery upon the flow of a stream of resin through the polymer processing machinery. The composition includes a mixture of purging agents separate from the resin that are poured into the stream of resin as an additive. The purging agents include a blowing agent to induce foaming of the stream of resin and an abrasive to scrub the resin deposits from the inner surfaces of the polymer processing machinery. The purging agents further include a surfactant to promote the flow of the stream of resin along the inner surfaces of polymer processing machinery. A binder binds the purging agents together in the mixture. The method includes feeding a mixture comprised of a blowing agent, an abrasive, a surfactant, and a binder into the stream of resin entering the polymer processing equipment.