Soak a cleaning rag or paper towels with white vinegar, and wipe over the plastic surface. This often cleans all dirt and film off the plastic.
Fill a basin or sink with enough warm water to submerge the plastic. Pour 1 cup white vinegar into the sink or basin per quart of water used.
Place the plastic into the water, and submerge for 5 minutes when possible. When this is not possible, hold the plastic in the sink and rotate consistently until all sides receive the same amount of water exposure.
Scrub the plastic with a cleaning rag or paper towels, and rinse with warm water. Dry the plastic with a clean rag or paper towel.