My Step Father gave me a T/C .54 cal. Hawken flintlock he had won in the 70s that he never fired. After years of shooting it I decided to refinish the stock. They must have sed polyurethane to finish the stock because no stripper would strip it. After sanding the finish off I used a steam iron to pull up the minor nicks and scratches but it didn't pull out the old stain. I remembered a friend of mine who used to buy and restore old roll top desks. After stripping them he used chlorine bleach to remove the stain. I applied the bleach with a stiff cheap paint brush and scrubbed it until got thick. Then I rinsed it with a garden hose. I repeated the process six times until I had removed all of the stain. The original stain was walnut and I applied Cherry stain and a hand rubbed sealant and finish. Poly should never be used on gun stocks, fine furniture or anything you have to refinish down the road.