Doublegun, Although I use hydrogen peroxide to clean BP and Pyrodex fouling, I don't use it undiluted or by itself. Rather, I use it with isopropyl alcohol (90% if you can find it) and Murphy's Oil Soap. The proportions are equal or 1/3 cup (or your favorite measure) of each, and is also known as "Friendship Speed Juice." It works, but if you use it to clean your bbl., make sure you don't leave the solution in it for more than 15 mins. and then flush, dry, and oil thoroughly. This stuff works quickly, but I get about the same results from an isopropyl alcohol, vinegar, water + a few drops of dish soap these days. Btw, I've had no rusting, pitting, or other harm to my guns as a consequence of using the peroxide solution.