Acetone will leach out all the oil, no problem....if you can get a long container the stock will fit in, fill it with acetone (make sure its pure acetone with no additives), let it soak, and the oil will be gone...

That is why its recommended to wear glove when working with it, it will actually suck the oils out of your skin, and give you contact dermatitis in some cases....

And it completely evaporates out of the wood leaving no residue, unlike oven cleaner (which I would never use)...but the wood will be DRY...

Acetone is the best stripper for most things, although I mix acetone, methylene chloride, and some toluene for a really super duper stripper....but I have access to all those at work....

I like to use Simple green on stocks like that. I just spray it on and wrap paper towels around it, spray it down some more. Let it sit for a while and all the oil wicks out. Cleans the stock nicely too and it doesn't hurt anything including myself. I do use acetone for very stubborn spots but wear gloves for that.

A good method it to use a mix of boiling water and washing soda 1/4 cup to a gallon. dissolve washing soda in boiling water and submerge stock, weighting it down to keep it below surface.
Let soak for 24 hrs. it will raise all but the very deep dents, get rid of the gunk and bring any proof marks back to like new condition.
Let the stock dry slowly for several days. Then refinish with linseed oil cut with Japan drier (follow directions on Japan drier).
The only sanding you might need is with 600 paper to remove any whiskers on the wood.(prior to oil)
Do that in several steps. Sand, then wet stock lightly, let dry and feel for any raised grain, Repeat until no grain is raised.

I once picked up a Savage 755 shotgun.  The bottom 1/3 of the butt stock looked as if it had been soaked in used oil.

I bought some wood bleach at HD or Lowes and got after it.  Did a great job.  No trace of any stains anywhere.

Redid all the gun.  It was their version of the A5 with the steel receiver.  The later Model 775 used alloy.

It doesn't get much respect but it is a fine shotgun.

I would steam it very well with a wet towel and an iron to raise any dents and then I would get some wood bleach and bleach it two or three times, really well to get it white like,  then rub it down with your choice of finish you can use like a Brillo pad or something like that to smooth down the fibers. Then I would finish it off with tru oil.