Plastics make up only about 8 percent of the volume in the average landfill but represent a huge investment of energy and raw materials. Most plastics produced from petroleum materials by polymerization of monomers such as ethylene or vinyl chloride are thermoplastic materials and can be cleaned, melted, and re-formed. Thermosetting plastics can also be cut into pieces that are mixed with other plastics or used as fillers. High-density polyethylene (HDPE) and polyethylene terephthalate (PETE) are the most widely reused plastic materials, but polyvinyl chloride (PVC), polypropylene, and polystyrene account for 5 percent of the recycled plastics. In 2001 80 million pounds (36 million kilograms) of plastics were recycled in the United States. Recycled plastic materials are used in the production of bottles, fabrics, flowerpots, furniture, plastic lumber, injection molded crates, and automobile parts.

According to the Environmental Protection Agency, Americans discard 120 million gallons (454 million liters) of oil each year as a result of automobile oil changes. Virtually all this oil can be recycled, and most states require recycling. Used motor oil contains particulate matter and some chemical substances that must be removed during re-refining. As much as 80 percent of used motor oil is used with little change as a fuel for ships or industrial heating equipment, but this practice probably poses a greater danger to the environment than burning refined oil.