I am in the middle of adding a little life to a set of junk stocks. I soaked them in acetone as already stated and it did indeed eat all the oil and gunk out and off the wood. I was worried about the medallions since they are riveted in but they were fine. Any polymer backed versions will likely die in the acetone soak though. I didn’t stain but I’m using Tru-Oil to refinish them. I will be posting before and after pics if you can wait a while.