Thanks for the tips. I have a Remington 'old army' .44 that has a nice brown patina but also has some flaky rust spots that I have been intending to remove. I like the idea of soaking them in a penetrant then using a brass case or punch to dislodge them. I also have a 1925 Colt .22 auto (pre-woodsman) that had some flaky rust in a few spots. I soaked it in penetrant then used Brownells brass wool. Dark spots remain, but that is far better than rust. By the way, what a wonderful .22 pistol this is, and it definitely has a Luger influence in it's shape.