Anyone have a way to get old brown colored brass, brite and shiney again? I have a handfull of assorted calibers of range brass that just won't shine up at all with cob, walnut, nufinish, or Lemishine. Some of it I keep throwing back into the tumbler, probably has spent a week being tumbled and still nadda, just brown. I have reloaded brown brass before for my own use, never had any issues but this stuff is brass I want to trade for calibers I need. Any ideas?