2005 4cyl ignition system tune up: found oil in the spark plug well.

I'm having misfires and occasional threats to stall out due to an aging ignition system, and I'd like to know if its normal to be finding oil in the plug well and on the coil boot.

Here's what it looks like:

boot: imgur: the simple image sharer

down the well: imgur: the simple image sharer

Is it normal to have? Should I clean it out? (if so tool/chemical/method for doing so?)

If it's not supposed to be there, how could it have gotten in? I did spill a bit around the oil tank cap a couple of month back, that's the only reason I can think of for it.

Thanks for any advice.