Will not harm ANY METAL or Primer. Will not stress brass. No Ammonia. No Buildup. Suitable for corn cob, walnut or other media. Cuts tumbling time in half. Cleans, polishes & protects brass & nickel. Eco-safe product. Removes: Oxidation, Tarnish, Lead Buildup and Fingerprints. Safe for:Safe when used on ANYMetal. Will not Deaden the Primer. Will not Stress or Imbrittle Brass. No Ammonia. No Buildup.