Substitue for brass polish from reloading source
Folks, before I could afford a tumbler, I cleaned my brass in a 1/2 solution vinegar and water by soaking the brass in the vinegar and water, shaking it around from time to time, then after a couple of hours I'd rinse the cartridges out with clean water and dry them over night. The vinegar changed the brass color a little bit but I didn't see any other adverse reaction to using the vinegar.