Brownells sells a material, I can't recall what they called it, but it is calcium carbonate ( chalk) that you mix with alcohol or other quickly drying liquid, then paint onto the oily stock . As the mix drys, it sucks oil out of the stock. Then you just brush it off. But I'm lazy so I just left my oily M1 stock in the sun on the deck ,on cardboard to protect the deck, then every hour or so wiped off the oil that bled out. It took 2 days of hot sun.