I've never used a bluing to repair small scratches, etc. and would like to get some input from others who have used the cold bluing options. I have reshaped or modified a few sights and have a small scratch on the barrel of my 1895CB that I would like to repair. Actually the scratch is really where the bluing was rubbed off from wear of a ladder sight. What bluing should I get and what kind of experience can you offer in surface prep, etc.?