What do you guys use to tumble or clean brass. I have a tumbler and have been using the same media for a long time and it's getting pretty dark. What's best, and how long does it last. When it says media is "treated" does this mean with a type of metal cleaner, and does treated last longer than non-treated. I remember reading somewhere about a guy who bought some sort of hamster bedding from a pet store to use as media, any truth to that?