I have 2 winchester model 12 20ga's that belonged to my grandfather. I believe one was from 1916 or 1917 just before he went off to WWI and the other was from the 1930's. They got stored in a humid environment and now the blueing is somewhat shot. I was wondering if there is a way to restore them without lowering their current value. I also don't want antiques with a brand new blueing job and no longer look like antiques.