RangeMaxx Brass Tumbling Media removes dirt and carbon fouling from brass cases before reloading to keep reloading dies in top condition, and reloaded ammunition as consistent as possible. Tumbling Media can be used repeatedly but should be replaced periodically for optimum performance. Walnut media works best for deep cleaning of heavily tarnished casings; corncob works best for once-fired cases and for polishing. Available: Corncob, Walnut. Cancer and Reproductive Harm- www.P65Warnings.ca.gov. Type: Tumbler Media/Polish.