I thought I would post an easy way to clean muzzle brakes. I usually take them off to clean the barrel, and after 3 or 4 matches they need cleaning. I submerge them in a plastic cup filled with Evaporust, it completely dissolves the carbon and powder residue. You can speed it along with a bore brush in the holes, but it really isn't necessary. A few hours soak is usually enough, it doesn't affect stainless steel, I don't know about blued finishes, but I would be careful, because bluing is a form of rust. You can find it at any hardware store.