I acquired this old percussion double barrel. Based on the Proof mark (which is kind of worn) it is a Manufacture St.Eteinne (maybe mid 1800s):
To be clear it is not in great shape. I would not fire it on a bet (Barrel is very thin at the muzzle) but I was looking at cleaning it up for display. I do not plan on selling it but would prefer not to destroy whatever value it still has if any.
The problem I see is that it appears someone tried to paint it. Not sure if it is brushed on paint or a poor attempt and cold bluing. I am looking for a recommendation on how to clean it or even if I should tor clean it as I don't want to devalue it even more. Below is a photo, you can see what almost looks like brush marks and runs right up to where the handguard is. They apparently did not bother taking it apart to paint/blue it.