Rust is an awfully generic term. I've cleaned up a couple guns that were almost totally brown. A little very fine steel wool and oil left them in almost perfect condition. Last year I bought a 12 ga Baker Damascus barrel that had some very localized but fine grained rust about a third of the way from the breech end. I had high hopes that they would clean up, but the pitting under that narrow strip of rust actually perforated the left barrel clear through and ate much of the way through the top rib. My great buy turned into a $10.00 tomato stake. The rest of those barrels were in beautiful shape. I've been playing with a rust remover called Evaporust that I bought at an auto parts swap meet. It seems to do a good job of removing rust without attacking the base metal at all. It's supposedly safe and not the least bit irritating to bare skin. It does of course remove blue.
