Glad I tickled your funny bone. Guess I take myself too seriously, having seen wells go bad from petro-chemical contamination. I'll always remember a home inspection I did a few years ago, where a glass of tap water had pretty colors floating around the top when oriented to reflect light, and smelled like something most people would never, ever want to drink.
But I do find it interesting that the oil you use actually dries--where I come from, oil will stay liquid almost indefinitely, and doesn't dissipate. In fact, it usually likes to move when carried by groundwater.