Hardware is a general term that refers to the physical artifacts of a technology. It may also mean the physical components of a computer system, in the form of computer hardware which is what is referred to here.
Computer recycling is the recycling or reuse of computers. It includes both finding another use for materials (such as donation to charity), and having systems dismantled in a manner that allows for the safe extraction of the constituent materials for reuse in other products.
Obsolete computers are a valuable source for secondary raw materials, if treated properly; if not treated properly, they are a source of toxins and carcinogens. Rapid technology change, low initial cost, and even planned obsolescence have resulted in a fast-growing surplus of computer components around the globe. Technical solutions are available, but in most cases a legal framework, a collection system, logistics, and other services need to be implemented before a technical solution can be applied. According to the U.S. Environmental Protection Agency, an estimated 30 to 40 million surplus PCs, which it classifies under the term "hazardous household waste", will be ready for end-of-life management in each of the next few years. The U.S. National Safety Council estimates that 75% of all personal computers ever sold are now surplus electronics.