As a woodworker Olive oil is not recommended for cutting boards because it will go rancid over time. This is why they recommend food grade mineral oil. On pipe bits Olive oil would not be a problem, but I would hesitate putting it on briar where it can soak in. Of course briar pipes are not cutting boards, but if it goes rancid it will stink. Food grade mineral oil is a safer choice. No one is certain what Dunhill used for oil curing. I have guessed it to be Walnut or Almond and have used both to heat cure briars I've turned. I have also used both of these oils on vulcanite bits. If mixed with fine pumice and applied with a fine cloth its good at removing oxidation.