I played with tumbling media for about a year before I settled on corn cob blast media (blast media is much better than pet litter). I tried a dozen different media from beach sand to rice and dried beans/peas, wood chips, glass beads, BBs, and some I can't remember right now. Corn cob blast media 14-20 grit, is harder than pet litter and better quality controlled. In my estimation, cob blast media is best for all around case cleaning...