Get some whiteing, I think Brownells has it, make a paste with mineral spirits and apply to stock and let set for a few days, weeks. It will draw oils out of the wood. Alternatively you could use cornstarch or even flour, make a paste with a bit of water, apply and let sit for again several days to a week , whatever it takes. It might take several applications. I am not to fond of the idea of using oven cleaner, which is lye on a stock. Lye plus animal fat combines to give soap, I do not know what the end product of lye plus petroleum based oils would be. My concern would be that the lye would damage the wood, and it will, plus cause corroison of the guns metal when reassembled.