Whatever polish or wax I most recently used on the truck, gets put in the reloading room and I shoot a little on top of the media with the tumbler running. I use corncob and run it for 10 or 12 hours to get nice shiny brass every time.

I figured the other day that my older Frankford Arsenal tumbler has about 5000 hours on it with nary a problem so running it so long does not seem to be harming it one bit.