AR Man - Hands down the best way to remove cosmoline from wood is as follows (done this on over 30 rifles): Douse all wood parts with boiling water. Then spray liberally with oven cleaner, the stuff without lye. Let this soak in for 15 minutes, then scrub with a toothbrush. Rinse the wood with boiling water and rub off the surface wetness with old rags. Let the stock air dry for about an hour, then rub it down with acetone (be carful not to breath the vapors or get this stuff on your skin). Let the stock again sit for an hour or so. Then lightly go over the entire surface with 0000 synthetic steel wool (has no oil residue). Don't ever use sandpaper on an old military stock; that can remove any cartouches and other "character" marks. The hot water soaking will raise many if not all dings in the stock. Any remaining dings that are not too deep can be raised by placing a wet cloth over the ding and applying a hot steam iron to it briefly. When done, let the wood sit for a week so that it dries completely. For a real nice authentic military finish on your Mauaser, apply three to five coats of boiled linseed oil, rubbing is briskly and waiting at least 24 hours between each coat. While you are waiting for the last coat to dry, mix up the following: equal parts of boiled linseed oil, turpentine and bees wax. This you will apply as a finish coat and it will give the wood that real nice satin sheen and provide great protection. Apply this mixture to the stock at least once a year or sooner if exposed to adverse weather.
Have fun!
BTW - Kerosene works great in removing cosmoline from metal, as does brake cleaner, carb cleaner, gun scrubber, etc. - all hydrocarbon based. Please dispose of the residue safely.
Noban