I have not tried this but it sounds reasonable. A friend of mine at a local shoot mentioned that when his brass is extremely dirty, such as stuck on mud or sand, he uses rice in his tumbler. Cheap enough to use more than once. I thought it was worth passing on to all the reloaders on the forum. Anyone ever use this method?
I prefer to clean thoroughly with walnut and dillon case polish and then follow up with clean corn cob. The walnut does a great job of cleaning and knocking the crud off and the corn cob puts a smooth, slick finish on the brass.