One poster mentioned cleaning a pitted bore with ??? and four 0 steel wool. I prefer to be much more agressive and use fairly coarse emery cloth soaked in oil, repeatedly pushing breech to muzzle, being careful not to mess up the square corner at the breech. Much less invasive than honing but very hard on the pits and rust. I keep the emery paper very wet with oil to minumize scratching. The barrels must be mounted in a vise to apply enough pressure to do any good. I have had great results with this method.