i asked a similar question a bit back and got some good answers. my last tumbling efforts was 70% cob 30% nut with 2 dryer sheets seemed to do a very nice job with minimal dust.
stop up in the new member forum and intro yourself
"Gun control: The theory that a woman found dead in an alley, raped and strangled with her panty hose, is somehow morally superior to a woman explaining to police how her attacker got that fatal bullet wound." — L. Neil Smith