From the seller's side... An 80 year old break action single shot 12 gauge for $50, and a prospective buyer says, "It's been re blued! The collector value was lost right there!"
Actually that one can be applied to either side of the table. (Never have quite been able to figure out how a refinish on a classic automobile is not held against its value, but if someone wiped down a firearm with an oily rag, it instantly ruined all value.)
