Cleaning brass is not science. Throw in whatever you shoot, pour in some of the cheap ($26 for 40# delivered, on line) a little car polish and let it run. If you find a dirty one when you load, toss it or, clean it up with an screwdriver, etc. and put it in with the next batch.
If you don't get good movement of the brass and media, take some out.
Education teaches you the rules, experience teaches you the exceptions (Plagiarized from Claude Clay)