Recyclable materials left over from manufacturing or building processes and consumption. Often scrap is considered waste, but actually has monetary value and can be sold to recyclers who then sell the re-processed scrap to industries. All sorts of discarded metal can be sold as scrap–including aluminum, copper and steel. Scrap recycling diverts tons or waste materials away from landfills. For instance, in 2007 the US exported over 10 billion dollars worth of scrap steel.