That's a good old knife! Any of them made in Solingen back in the day are. Today, not so much. The All About Pocketknives is a good website with quite a bit of info. And you can clean it up some and won't really hurt the value. But it's tedious work. There's some stuff called Colonel Brassy that will clean every inch of that thing, but you have to be careful with it on guns because it'll take the blue right off. Don't ask me how I know, lol. But it would clean those bolsters and blades up. Heck, that little knife would probably make a good every day carry knife, if you weren't afraid to lose it or pry on something, lol.