Hi there I bought a 1984 300SD and the passenger side keyhole was filled with some kind of cement/rubber, I don't know. I can still use the drivers side keyhole... sometimes. I can stick the key in fine, and it locks fine, but something doesn't seem to line up inside when I try to unlock it. When the weather is cold, it can take 10 or 20 tries. Would WD-40 help the situation or totally destroy everything?