I am assuming its not fuel laying on top, as you have recently stripped the plane..to recover. So I imagine its IN the wood? There are different ways to pull fuel oil out of wood.

I used to use a stain removal aerosol called K2, you sprayed it on and let it dry out, then dust it off.

Most types of body powders will pull moisture , heck I don't know what cat litter could hurt !

I am afraid I can't recall all the other variations to remove fuel oil..If you search it you will be able to find other ways.

Also they make some brush on adhesives to help covering stick, sig stixit and a red baron has a covering adhesive..it might be worth trying.

Your name makes it pretty obvious you served in the military..thank you so much for doing the hard job of protecting our country.