I used corn cob for a long time. I added Dillion�s to polish my brass. I used treated nut shells for a little while. I now only use walnut. The walnut cleans the best but doesn't really polish. I do rinse and dry my walnut and reuse it, it seems indefinitely. The cleaned brass retains the perfect amount of size lube for reloading. I was getting wrinkles when sizing highly polished brass from too much sizing lube.