I have a .50 caliber in Stainless Steel. Went deer hunting in the mountains for a week. It got foggy and damp a little drizzle, that kind of thing. I would wipe the gun down on the outside every night. I did not, however, take it completely apart and wipe everything down. When I got home and took it apart, I had a lot of little surface rust spots on the Stainless Steel on both the base under the chamber frame area and the framearea above the trigger assembley area. I brass brushed the rust off with Blue Wonder. However, there are dark greyish "stains" left behind on my "stainless steel" were the rust spots used to be. How do I get the stains off. I don't want to steel wool it to the point where I have a shiny spot. Any help would be appreciated.