Do you know what happens when you start the tumbler in the evening and forget about it until the next day? The brass comes out really shiny!
Here's the result of about 16 to 18 hours. Some of this brass is recent production, but the .30-06 is Korean war surplus with 50 years of tarnish. It looks nice but I don't think I'll make a habit of such long tumble cycles.
Before and After: