Do you, and if so, what do you use?
I've only tried a couple of batches and had mixed results. One batch was tumbled with stainless steel shot for 4 hours before the colour started to fade. Rings from another supplier couldn't be tumbled for 5 minutes before the colour went.
I took delivery of some crushed walnut shell and crushed corn (impregnated with polish) this afternoon. I'm on the second hour with the walnut with no fade. A couple of questions spring to mind:
Do I need to put anything in with the walnut?
Do you think the polish on the corn will strip the colour?
This is all with a rotary tumbler by the way.