I'm not an expert by any means in gun restoration, but I have done a fair amount of phase 1 cleanup of not only my guns, but guns for friends and family. If the finish is pretty my gone off the gun, it won't hurt it to do as suggested by using steal wool and oil. Some of the bad spots I have actually used a bit of Naval Jell. Just make sure you neutralize it with oil after your through. The stock can be Linseed oiled or tru oil what ever you have. Just make sure the rusting doesn't interfere with the overall functioning of the gun - in other words, make sure it's safe.