I would try the local harware or garden supply for some of those little rocks found in pebblecrete and give them a try on some scrap .
What ever you use needs to be dry otherwise it will form a clump of media in the tumbler / rumbler .
There as far as i can see there is a difference between a tumbler and a rumbler as the first rotates ( can also vibrate at the same time ) and the contents tumble , hit each other and what ever media you are using , a rumbler vibrates but does not rotate but the result is similar .
I use a tumbler to moly coat my bullets and a rumbler to clean cases .
I use corncob media for rifle cases and it is also used as labaritory bedding for lab animals , i then add some cutting compound used to restore car paint and rumble for 1 hour to dispese then allow 1 day to dry .
If it is not allowed to dry it sticks to the inside of the case and is a mongrel to get out !
This would also be good for brass , copper and aluminium .
Ian
Edited By SLOTDRILLER on 25/09/2012 05:21:10