Here is the FAQ page from Fulton Armory. I've followed this with good results:
My CMP M1 stock has a few dings and is very sticky. What can I do to clean the stock? Do I sand it? What do I put on it after all is said and done?
The M1 Rifle was originally manufactured with one of two finishes: linseed oil or China/Tung oil. Towards the end of WWII the linseed oil was supplanted by Tung Oil, a finish which was used, I believe, during '50's production. Refinished stocks were, however, generally refinished with linseed oil.
In all cases the finished stock was simply dipped in a tank of linseed or Tung oil for a few minutes and then allowed to drain dry.
Stocks that come from the CMP, whether as parts or on a rifle, are often coated with that sticky goo called cosmoline. Even those that are not are likely to be oil soaked or stained in one area or another.
Here's what I do. To strip the old finish and remove oil & dirt, I use Easy-Off Oven Cleaner (the Heavy Duty variety). Spray it on, let it soak for 10-15 minutes, and then rinse off with very warm water while scrubbing with a Scotch-Brite pad. Usually one go with the EasyOff is sufficient, but I have had to repeat the treatment up to twice more.
When the stock has dried I follow up with a coat or two of Minwax Natural Stain (unless I'm getting creative) and finish with two or three coats of Minwax Tung Oil finish. Minwax Natural is clear; it simply seals the grain.
Except in extreme cases the strongest abrasive I will use is 00 steel wool. Usually a mild going-over with 00 before and after the first coat of Natural stain, then 0000 thereafter. I use my thumb to cover the cartouche and Proof stamp, in turn, to assure I don't further degrade it. I repeat the process with the Tung Oil; after buffing damp (10-15 minutes after application) with a balled-up nylon stocking or pantyhose (really!), allow drying for 24 hours then buff with 0000 steel wool. After the second coat, buff with 0000. After the last coat, buff with the stocking.
The result looks military but is more durable. I've done more than a dozen M1 and M14 stocks this way, with total satisfaction. If you're able to attend the OGCA shows (e-mail me if you wish to be sponsored as a guest), stop by the GCA booth. I generally have my CMP rifle and my wife's CMP rifle there, refinished with this method.
http://www.fulton-armory.com/StockSave.htm