I use citric acid in hot water. About 1-2 teaspoons per gallon. I about 1/2 fill a 1 gallon spackle bucket with brass, add hot water and the citric acid and a drop or two of dish detergent, put the lid on and swirl/mix for 15 sec and let sit for 5 min, swirl again and let sit another 5 min. Next I rinse them a bunch of times, spread the brass out on a towel overnight and they're done ready to be loaded.