Metal scrap is generated from a number of sources including industrial processes, construction, waste collection and household rubbish. As some scrap may be contaminated or too large to transport economically, scrap processors have invested in ways to clean or upgrade the scrap such as shredding / granulating and baling. This makes it more usable for downstream consumers which are mainly melting plants producing alloys, remelts or semi-finished products such as sheets, hardware, wires and in the case of lead, batteries and paints. Where Copper scrap is traded, much of the lower grade material is recycled by refineries from which new Copper cathode will be produced and the process and life of that starts all over again.