I would like to add one point to Drews excellent link with solution(s) to this problem. I have found that an initial dousing with Easy Off* Oven cleaner with an oil finished stock can speed up this process. The cleaner seems to leach a lot of the oil out of the wood in very little time. When I have done this (outdoors) I've sprayed the stock with cleaner and set it out in the sun and wiped the leached oil off with paper towels. This process can of course be repeated but I would finish with either whiting or acetone then go to alcohol.
*Or any other brand.
Jim
