Try grocery store grade clear ammonia and a Scothbrite pad. Rinse with cold water, reapply RLO and buff out with fine steel wool. Repeat as many times as you desire. Never-ever-ever use lye based oven cleaner. It will damage and discolor or grey most gunstock wood and will destroy wood like Australiancoachwood. No offense to anyone intended but it's a lazy mans method and does more harm than good.