Re: Whats With My Gas Cap
Don't worry about the oil is more than likely just some oil left from a drip of your gas/oil mix that the gas evaporated out of.
Now about that cap....most are problematic. Here's a couple of "helps".
Drill a tiny hole in the top of the cap. This helps pressure escape instead of it building up and leaking around the gasket. The tank should be vented anyhow, but a lot of them seem to have a problem there.
Don't fill it all the way up.