Nitro solvent is used for skeet and trap shooters to help remove corrosive acid residue from plastic shot shells. Copper solvent is used to remove copper or gilded metal fouling and powder residue in all firearm bores. Maybe harmful around painted metal, plastic, synthetic stocks or varnished stocks. Ammonia based. It is recommended that the firearm be re-treated with Gun Treatment or Synthetic CLP Gun Oil after use.