I've been using a product from Pro-Shot they call the metal care cloth. Comes in a Mylar bag and is treated with something. Rag is pink and removes powder residue like magic. Doesn't seem to have any effect on the bluing either. Just give them a quick wipe down with the metal care cloth, then wipe them with a clean cloth.
Mark Lane to William Buckley: "Have you ever referred to Jessee Jackson as an ignoramus?"
Buckley: "If I didn't, I should have"