One of my shotguns was left in the closet of my dad's trailer for a few months after grouse hunting (which I didn't know about...) well, when I found it, there was rust everywhere!! I was so mad... it was my 1st shotgun, which my dad gave me when I was 11! Anyways, I thought there might have been too much damage to save it, but I stumbled on this thread a few weeks ago... I tried Huntbears advice: I smashed down the mouth of a spare brass case, rubbed some Hoppes gun-oil on a big patch of rust, and scraped it all off! I'm absolutely floored by how well it worked!! The gun looks almost brand new!! Thanks Huntbear!!