So I recently bought a Finnish captured M91 and the stock is in great shape physically but looks like it is covered in mud and tar. So what I am hopping to do is clean all the junk off the stock and leave the patina as untouched as possible. I have heard about using stuff like goo-gone and boiled linseed oil, but I am not sure how that would effect the patina. I will post pictures as soon as I can.