recovery of paper fiber for reuse for waste paper materials containing plastic sheet and film is facilitated by the combination of a pulper in which the waste paper materials are pulped in a pulper equipped with a junk remover connected with the bottom of the pulper tub by a chute and provided with a pump constructed and arranged to maintain the hydrostatic head in the tub at a higher effective level than in the junk remover tower by circulating liquid from the tower back to the tub . the result is to cause transfer of the plastic and other lightweight trash to the junk remover for removal by its conveyor buckets and to prevent accumulation of lightweight trash in the tub to the extent that it interferes with extraction of the defibered paper slurry .