I'm sure you'll get lots of different advice here but I'll stick by my tried and true method for old oil. Spray on some Easy Off Oven Cleaner and it will literally boil the oil out of the wood. Which can then be scraped or steel wooled off. It will take repeated sprayings and this should be done out of doors or in a well ventilated shop.
Jim


The 2nd Amendment IS an unalienable right.