I’ve used two oddball things - one had glass beads (like the ones my kids use at camp to make bracelets out of, had a ton of them in sack and they worked well), second was copper bb’s. Had a lot of them and never used B.Bs anymore so I used them. Both seemed heavier than rice or corn that I’ve used in the past... although I don’t think I would have gone out and bought beads and bbs just for this.
Crusher- kitty litter is a good idea... as long as it’s unused.