Used and recommended by major firearms manufacturers, Lucas Oil Gun Metal Polish & Tumbler Media Additive cleans and polishes factory firearm finishes like blue, nickel, stainless, aluminum and brass. Its acid and ammonia free formula safely removes stains and rust from metals with no hard rubbing while protecting treated surfaces from oxidation and tarnishing. Great for use as a tumbler media additive to remove oxidation, powder residue, fingerprints, and other contaminants leaving brass and nickel cases bright and shiny. Use with walnut shell or corn cob tumbling media to reduce cleaning time by up to half compared to using plain media alone. This additive contains no acids or ammonia, so it wont damage primers or brass and doesnt smell. Not for use on cold bluing.