Metal refuse is a term used to describe the waste materials that are produced during the process of metalworking. SCORIA (6 letters) is a type of volcanic rock that is often used as a SLAG material in metalworking. SLAG (4 letters) is a by-product of metal smelting and is composed of various impurities that are removed from the metal during the smelting process. SCRAP (5 letters) is a term used to describe any leftover pieces of metal that are not used in the manufacturing process. DROSS (5 letters) is a type of waste material that is created during the refining of metals and is composed of various impurities that have been removed from the metal.