I use MPro7 and a bronze brush from Brownells. It cleans the carbon right off of stainless guns and cleans blue guns without much damage to the gun. Actually, I just get the lead off the face and and leave the carbon rings. The bronze brush will eventually wear on the bluing, but I have an old 586 with AAA serial number that I bought new that has been scrubbed a lot and still looks pretty good. Heavy use and cleaning will eventually show use.