According to the US Environmental Protection Agency (EPA), CDs and DVDs are manufactured by combining various mined metals (aluminum, gold, silver, and nickel) with petroleum-derived plastics, lacquers, and dyes. Each year, billions of CDs and DVDs are manufactured and millions end up in landfills where they degrade, polluting groundwater.
As for jewel cases, most are made from of Polyvinyl Chloride (PVC), an inexpensive petrochemical-based plastic that is difficult to recycle at most recycling centers but there are a handful of companies that recycle them into high-quality plastics used in auto parts, office equipment, alarm panels, street lights, electrical cable insulation, new jewel cases, and more.
Recycling these discs and cases properly*, will stop unnecessary pollution, conserve natural resources, and help slow global warming.
*It is estimated that it will take over 1 million years for a CD to completely decompose in a landfill