Recently picked up a Smith & Wesson revolver and in the process of going over it I've noticed a build up of carbon the the cylinder throats. I've tried everything to try and remover this carbon, carbon remover and let it soak, Butch's Bore Shine, CR-10, Montana, Shooters Choice, etc, etc. (yes, I have a bore scope) I even used a Lewis Lead Remover and twisted it in the effected area and still there's a bunch of lead stacked up. You guys have any suggestions on how to get this stuff out of there? I don't want to go to an industrial penetrating oil for fear of messing up the bluing or etching the cylinder throats. You guys have any suggestions? Thanks. BCM