I've had a real hatred as you know for many years after being almost incapacitated y their stings in my hand and mouth. I feel no sympathy to their destruction, although I do like to see them go in a quick and humane manor - like I would any of God's creaters ( I imagine God must have been having SOME DAY the day he invented the yellow Jacket - lol )
I have read that you can poison some food source that they would hourd onto if left alone - something that will safely be kept away from pets, but close enough to the yellow jackets so that they race to it to gather as much scavenged food as possible. I don't know if poison used for rats or other varmit does the job, something tells me that bug poisoning would keep more of them away then attract them.
I can only imagine the safe way is to hang the poisoned food source from a tree by a string and hopefully they will drop like flies as they eat the poison.
Maybe even check with Agway or other farming centers Al, you might be missing a product already on the market - I sure know that every time I go into a store, it has new and neat ways to kill stuff