Earlier this year, Ford announced it would begin acquiring some of the more than 3.6 million pounds of paper U.S. money that gets shredded each year and recycling it into plastic that will be used for parts such as trays and bins. The plan does Earth a solid while providing the company with cheap alternatives to increasingly expensive petroleum. And the Blue Oval isn't alone—most car companies are exploring new uses for refuse. Try to match the various flotsam with the form it takes in its automotive afterlife.
CARPET FIBERS [B] When carpet is broken down to its chemical parts, it can be reformed into plastic. Ford has used 4.1 million pounds of carpet to make engine head covers for Escapes, Mustangs, and F-150s. The plan helped Ford cut petroleum use by 430,000 gallons in 2011.
SOYBEANS [E] Since hydroxylated soybean oil resembles petroleum, Ford uses oil from 31,251 soybeans to produce seat and headrest stuffing for eight models of Ford and Lincoln vehicles.
CARDBOARD [D] GM repurposes cardboard boxes sent to its plants in the cushioning above the headliners of its Lacrosse. The 4 metric tons of reused boxes not only saves money; it also lowers GM's CO2 output by 14 metric tons each year.
SHIPPING MATERIALS [I] About 25% of the composition of GM radiator shrouds comes from shipping materials (packing peanuts, etc). GM plants reduce annual waste by about 200,000 pounds this way.
SHREDDED TIRES [H] GM grinds up worn-out test tires and reprocesses the rubber into air baffles (which sit near the radiator) and water baffles (found at the base of windshield wipers).
AIR DEFLECTORS [F] Car making produces lots of scrap metal. In 2011, GM melted down 101,619 tons of aluminum and turned it into transmission cases.
OIL-SOAKED CONTAINMENT BOOMS [G] After the BP oil spill, barriers were placed in the Gulf to contain the oil. Chevy turned 227 miles' worth of the oil-soaked booms into a slurry used to make Volt air deflectors.
VOLCANIC ROCK  A Hyundai uses the volcanic rock that's strewn across Hawaii in the finish it applies to the pillars in Elantras. While the rock comprises only 0.5% of the mix, it gives the pillars a cloth-covered look and makes scratches less obvious.
SCRAP DENIM [C] Ten pounds of denim end up as insulation in each Ford Escape dashboard. That's roughly 25 million pounds of jeans each year.
A version of this article appeared in the November 2012 issue of Fast Company magazine.