I have a tube (34 x 4) that has a mixture of ATF and acetone in it. I put my skeet tubes in it before a match and let them soak for at least a day or more if possible. It is hard to believe the stuff that come out when you run a brush through them but they are CLEAN. The tube is in a stand and must have a tight lid of something acetone doesn't attack. Do not, put a barrel with white plastic beads in it.

bill