Copper piping Good furnace charge material. Undesirables: Soldered joints and iron attachments. 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