I've been using corn-cob pet litter in my tumbler, but read somewhere that the walnut pet litter cleans faster. I don't polish my brass to a shine I just run it till its clean. I checked out some walnut litter at a pet store, it is a lot finer grain than the corn-cob does it leave the brass dusty? I have a bunch of corn-cob on hand, but thought if it would speed up the process I'd mix a little walnut in with it.