*facepalm*
I can't even think of anything to say. I think wes coveted it all!
Bob. Simply put, when you want to paint or oil something, you want zero contaminants. Not deliberately introducing them. I have never heard of anyone using WD40 in luthiery, in fact I don't even use the stuff as a lube, it's dreadful!
I even cringe when I see people wipe shellite or even water over timber for photos. When I spray my sealers I want them sprayed on raw timber, not timber that's been molested with something that could ruin the finish