Copper chops Good furnace charge material. Undesirables: Plastic and excessive levels of tin, lead, nickel, brass or aluminum. Use the arrows the cycle through the different materials which define what is acceptable for Warrenton Copper. Burnt transformer wire Mixed #2 copper Copper chops Copper piping Chopped enameled copper wire Mixed #2 copper Fine enameled wire Mixed #2 copper Copper pieces #2 tinned bus bar and punchings Copper turnings Tin-plated alloy #194 #2 burnt copper wire and tubing Mixed #2 copper