I'm in charge of cleaning and polishing the M1909 brass for my honor guard. After each funeral, my captain gives the family a pouch with the nice shiny brass to the families after the flag is presented. Lately I've been having some difficulty getting the brass clean. I de-prime the cases and wash them in hot water with some Birchwood Casey brass cleaner. Then I soak them in my Hornady sonic cleaner and dry them completely. Then I tumble them in my vibrating type brass polisher with corn cob and Lyman brass polish. I did this last step twice, but there was still dirty film left on the cases. I even put a couple of used dryer sheets in with the media when I tumbled it. Should I try Walnut media? I used that before, but it left a red residue on my brass.