Iosso Case Polish cleans and polishes brass casings to a high luster. It removes powder fouling, residue, oxidation, tarnish, and discoloration. Add Iosso Case Polish to the media before tumbling. It works with the media to reduce tumbling time and gives brass a like-new finish. Use Iosso Case Polish on soiled casings or on casings that have been pre-cleaned with the Iosso Case Cleaner. It leaves the casings with a highly polished look and keeps them from re-tarnishing for a long time. Now USDA Certified Bio-Based Formula. No petroleum distillates, no odor or VOC.