Years ago when I was doing quite a bit with the Garands they were pouring in from Korea and other countries till President Clinton put a stop to the rifles returning to their birthplace. They were running about $249.00 and were not the old DCM pre CMP rifles. Anyway I would get rifles with stocks totally soaked in oil and grime. If a stock looked worth salvaging and showed promise here is what I did with the wood.
I would fill a deep sink with scalding hot water and add a small 1 Lb container of TSP (Tri Sodium Phosphate) to the hot water. Then throw in the wood and yes, that is a rock holding the stocks down. After about 30 min I would use a scotch brite pad and rub the wood down and place it back to soak. I did this for about two or more hours letting the TSP draw the oils out of the wood.
Following a good soaking and scrubbing down the wood was laid out in the sun to dry. During winters I would place it in front of the furnace heater ducts.
Then light sanding and finally rubbing the wood down with 0000 steel wool. Make sure the wood is clean, no dust, dust is the enemy. I used canned air and a tack cloth to remove any and all sawdust.
That done I used Birchwood Casey Tru Oil but any Tung Oil or Boiled Linseed Oil can be used in any number of ways. whatever trips your trigger I guess. I liked Tru Oil as when worked right you can get a beautiful finish.
I left the above rifle with the natural "orange stock" look of the birch. Once assembled the rifle took on a nice look. I left the original DoD Cartouche in tact and the stock would be correct, not that it matters much since it is a post WWII rifle and late Korean era gun in this case.
Brownells also marketed a "Whiting Paste" which worked very well for drawing the oils and grime out of stocks. Worth a shot if you get into it.
Ron
<EDIT> Forgot to mention TSP is a common cleaner and can be had at any Lowes, Home Depot or home improvement or hardware store and is really inexpensive, I forget the cost but it isn't much. </EDIT>