the present invention provides improved systems for plastic recycling . in a first embodiment for recycling hdpe milk jugs , a cold water wash step is used to remove bacteria - generated odor from milk jugs . in a second embodiment , a system for recovering pet and hdpe from soda bottles is disclosed . the separation stage utilizes a three - compartment sump to separate hdpe using water as the medium , and two further stages using heavier media for separation of pvc cap liners and aluminum from the pet .