My recipe, which is a combination of suggestions (found on the FMD forum) is as follows (thanks everyone) !
In a 3 pound tumbler tub, I add:
1/2 cup of natural aquarium gravel
2 - 3 drops of Dawn dish washing liquid
2 tablespoons of ammonia
1 handful of clad (1/4 to 1/3 cup)
Water enough to cover the mixture by about 1/2"
Tumble overnight
Note: After filling, I do weigh my tubs, just to make sure they are not overloaded (s/b be 3 lbs or less per tub / yours may be different). I use a Lortone 33-B double tub tumbler, so there's one 3 lb tub for the copper, and one for the clad.
Once the run is complete, I dump the tub, gravel, liquid, and coins, into a large plastic coffee can (Folgers I think), in which I have cut 1/2 holes in the bottom. While holding the can directly over an old window screen, I simply spray the water hose into the can, while swirling the contents around, allowing the gravel to fall out onto the screen, leaving nothing but the cleaned coins in the can. I then dump the coins onto a towel, and set everything else out in the sun to dry, and done. Once the gravel dries, I put it right back into the appropriate tub, ready for the next run.........
Coppers (before).......................................................................Clad (before)
(after).................................................................................(after)
(after)