I've washed my brass for years.
I don't bother tumbling it.
I put it in a bucket with some soap and hot water and shake/swirl it for a few minutes, then rinse thoroughly and shake to get rid of the worst of the water.
Then I spread the brass out on a sheet in front of my dehumidifier (in the summer) or by the furnace in the winter.
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza
Baby Jesus cries when the fat redneck doesn't have military-grade firepower.