Saving A Blued Finish

This is a gunsmithing question, but not limited to the 1911, so I put it here. I have a relatively old Marlin 336, JM stamped, straight grip, no cross-bolt safety, built around the 1976-78 timeframe. Someone left it sitting out in a barn for several years, so the outside of the gun has/had extensive surface rust, especially on the barrel and receiver. Most of it is just surface, with not a lot of pitting. I want to get the finish back to as good of a blued surface as I can, but without re-bluing it. Does anyone have any tips or tricks they have developed over the years? I have been using 0000-steel wool with lots of oil and a lot of elbow grease! Any help at all would be much appreciated! The rest of the gun is in good to excellent condition, and I plan on slicking up the action and working on the trigger. If I had the tanks et cetera, I would just strip it down and reblue. As it is, I am not quite there yet.