Engine degreaser and hot tap water. Let it run until you are getting the really hot stuff from the tank. The solvent will soften the goo, and the hot water will float it away. Be sure to reapply the oil as soon as you are done. Slobber it on. I leave things disassembled for a day so the wood won't get re-soiled with oil. And this gives you time to apply the linseed oilicon to the stock.