I had the neck of my Guitar off to make a few adjustments and when I put it back on I dabbed a tiny amount of a petroleum oil (grease) on the screws before reattaching the neck. After the fact it occurred to me that I should check to see if grease is bad on bare wood. Well, it's not ideal - so should I back the screws out and apply something else to them or should I just leave well enough alone. I just have to have something to worry about, ya know?!