This is the kind of oil you want for your wooden flute, pure sweet almond oil.  I have used almond oil on wooden instruments worth thousands of dollars. Most other vegetable oils will go rancid with time. This oil is non toxic, will not go rancid, smells good, and most of all protects the inside bore of the flute from moisture. The outside of our flutes normally do not need to be oiled unless there is a lot of finish ware.  It comes in a 4 ounce bottle with a flip-top dispenser. Four ounces will oil a flute bore 15 to 20 times depending on how much you use so it will last for many years.  I recommend using it in conjunction with our flute cleaner/oil applicator.