I tumble - well, vibrate, actually - for two hours. Why? Because that makes them kinda shiny, and that's a nice round number.
But I use walnut shell right now, with a pinch of dry brass polish added.
Incidentally, Electric's comment reminded me: I clean my polishing medium periodically by "tumbling" a couple of Bounce anti-static sheets. I cut each one into fourths and off I go. They come out filthy, and I can see that my medium is cleaner.
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If God didn't want us to own guns, why did He make the 1911?

Incidentally, Electric's comment reminded me: I clean my polishing medium periodically by "tumbling" a couple of Bounce anti-static sheets. I cut each one into fourths and off I go. They come out filthy, and I can see that my medium is cleaner.
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If God didn't want us to own guns, why did He make the 1911?