Some years back, I was restoring a lot of SKS's and Nagants. The stocks were VERY heavily oil and cosmolene soaked on all of them. I tried soaking one in mineral spirits overnite. It worked well but now the solvent had soaked the wood. I tried heating it to get the solvent out. The solvent soaked stock reached ignition temperature and burst into flame. It got a little exciting in the shop for a few minutes because solvent soaked wood is really hard to put out!!
I finally settled on a method that worked pretty well. Soak the stock in mineral spirits for a few minutes and brush it. Dry it with rags. Put it in several garbage bags and soak it with oven cleaner. Keep it heavily soaked for a couple of days. The garbage bags are to keep the oven cleaner from evaporating away. Then wash it with soapy water. Lay it in a warm place for a day or so.
I had to do a few of those stocks twice that way to get all of the gunk out but it did work well. It was safer than "applied heat" and not labor intensive. The bad news is that it really raised the grain on the wood so it took a lot of sanding to make them presentable.Keep yer powder dry, Mac.
Tuff-Gun Finishes. The Name Says It All.
Mac's Shootin' Irons
http://www.shootiniron.com