I've put this out there before. Here it is again. Try Dollar General or Dollar Tree clear ammonia. I learned it from a guy in Florida who specialized in restoring antique rifles when I was a kid. I have a Brownells plastic tub long enough for forends. Soak the wood, let sit a few minutes, then gently sponge and clean with a fine Scotchbrite scrub/sponge pad. Use a soft toothbrush for the inletting, nooks and crannies. Rinse with clear water and dry. Your wood will be ready for glue, patching if necessary or other repairs. Then just treat with raw linseed oil, or stain first if you want. Been doing it that way for 30 years. I work outdoors with it. It's cheap and easy to do and won't hurt a thing. Try it on a handguard or scrap if you don't believe me and see for yourself.