This is probably old hat for old-time reloaders. As a test, I put a handful of the worst tarnished and discolored 9mm range brass into a cup of 50/50 vinegar and hydrogen peroxide. Let it stand and walked away from it. When a came back a few hours later to check it out the mixture was bluish and the brass inside and out was like brand spanking new. Both hydrogen peroxide and vinegar are cheap but not as cheap as crushed walnut reptile bedding for use in a tumbler. But man o man, does it work well and fast and makes no noise.
I wonder how many reloaders clean their brass this way, or perhaps, clean some brass to look like new for those special reloads?
And oh, since I had no white (clear) vinegar, I used apple cider vinegar. My brass smells like apples. Just kidding.