This is a very old thread, but I wanted to add my thoughts.
I HATE YELLOW-JACKETS WITH A PASSION. A whole nest full attacked me when I was a child, and it's been a feud ever since.
Here's what I've learned about the little suckers.
1. They love sugared water (soda pop) and meat. Some people even call them "meat bees".
2. You have to get them before they breed, so buy yourself a couple of hanging yellow-jacket traps, and put them out right after winter. As the little suckers wander in and die,
leave them there! Some people say you should empty the trap, but that advice is dead wrong. Yellow-jackets are attracted by dead things, including dead yellow-jackets. Just let them pile up year after year. You'll notice less and less of them as the years go by, because for every one you catch early, another 50-100 never get born.
This is the only trap I've ever seen that works, and it works great!
Rescue - Reusable Yellow Jacket Trap Find them online or at your
local big-box store. Remember you will be buying the traps only this once, and you do not need to buy extra bait. Just hang them high and away from people and pets, then forget about it, and enjoy years of yellow-jacket free living.