I use Harbor Freight fine grit (24 grit) walnut media and fill Berry's/Cabelas 400 tumbler to about 1" below rim -
https://www.thehighroad.org/index.p...-thing-fa-brass-tumbler.926192/#post-12790152
I add one cap full of liquid NuFinish to new walnut media with tumbler running and use a stick to stir/break up clumps until all the clumps are gone before adding brass. I prefer to run the treated media on the "dry" side adding additional cap full of polish every several batches as using too much polish will gum up the media and leave gray haze on brass instead of cleaning/polishing.
Most clean range brass with surface carbon fouling/soot will clean in about 20-30 minutes (I add about 600-800 9mm cases until tumbling action just starts to slow down for fast cleaning/polishing). If I want some polish on brass, I will run the tumbler for 1+ hour. If I want mirror finish, I will run tumbler with corn cob media (Some will mix 50/50 with walnut/corn cob for cleaning/polishing)
Great deal. Do you have a link?