How can I prevent bees (or yellow jackets) from building another nest under my gas cap cover?

Imagine my surprise (and pain) when I went to fill my gas tank. There were about half a dozen or so under there and once I got over the shock, I realized that they had built a really small nest there.

Obviously I grabbed some rolled up papers and shooed them all out and dislodged the mini nest so I’m assuming they’re now at the gas station and unlikely to have followed me home.

But in assuming there’s plenty more where they came from and I’d like to prevent a reoccurrence.

I guess I could soak a rag in Black Flag or something and wedge it in there. But then I’d get it all over my hands each time I need to unscrew the cap and I’m really allergic to that crap and I’d rather deal with the bees.

Is there any kind of herbal or natural type of bee repellant that any of you know about.

How important is it to ascertain definitively if they were bees or yellow jackets? They didn’t leave the stinger behind in my finger so is that a definite indicator or no?

Hopefully some Fluther naturalists or scientists are hanging around here this weekend. (where is Incendiary Dan? Haven’t seen him around in ages.)