You obviously don't pick up the same brass I pick up.
In fact, right now I am washing brass because it's currently too nasty to sort and tumble.
I heard that. Some of it goes for 24 hours and STILL has tarnish.
I use mineral spirits and New Finish in walnut media. I load it, and throw the rounds in fresh corncob for about 15 minutes and most (key word here is most) of it shines like a diamond in a goats.....