I've taken to cleaning the cases first in a Simple Green/water solution in a Harbor Freight ultrasonic cleaner before dumping them into the tumbler. The cases come out of the solution clean of residue, but not shiny. That's OK - that's what the tumbler is for. I specifically do not use the ultrasonic cleaner as a polisher; it's only duty is to reduce the amount of spent primer lead dust that gets into the tumbling media. This approach works very well; the media stays clean a LOT longer and with virtually no dust issues. I can get 300 45ACP cases or approximately 150 30-06 sized cases in the ultrasonic cleaner at a time, so this step isn't all that time consuming.
I always tumble clean before sizing. Rifle brass will get a second brief tumble to remove the lube, and I keep a baggie of old corncob set aside just for cleaning off lube. Since I use Lee brass trimmers, I don't have to clean the rifle brass flash holes after the second tumble - the cutting tool's center pin does it for me automagically.
Truth be told, I never trim handgun brass. I suppose that I should, for certain chamberings, be more diligent in that area. But I'm too dang lazy to add that step for what is essentially non-critical practice ammo. If I was shootin' Bullseye, I would probably be tempted to be less lazy.
I never tumble finished rounds, since it doesn't make them shoot any better and they're already as clean as they need to be by the time I'm done loading them. I also shoot a lot of cast lead, and I see no profit in getting fine lead dust embedded into my tumbling media.
So, here's what that looks like for handgun brass:
- Wash in ultrasonic cleaner, rinse, and place on towel. Pat dry.
- Tumble in corncob
- Decap/size
For rifle brass, it's:
- Wash in ultrasonic cleaner, rinse, and place on towel. Pat dry.
- Tumble in corncob
- Decap/size
- Tumble off lube
- Trim to length