Here's my approach, after being stung twice earlier today and discovering the nest. Tonight after a heavy rain storm, I fully dressed in my snowmobile attire, pants, boots, jacket, gloves, and full face helmet. ( Very hot in July!) ( I suppose my motorcycle gear would have worked too, but felt safer with the snowmobile attie. I covered my two small flashlights with red paper I taped onto them and located the nest, It was only3 feet off the ground hanging below an unused boat lift. I carefully placed a pail filled with a quart of ammonia directly under the nest using my Kayak paddle. I then used a 10 foot stick to dislodge the nest into the household ammonia in the pail below. I walked away from the area and around the house and entered without them knowing what just hit them. I trust they will all be quite dead in the morning!
I've used ammonia on huge bumble bees knocking them right out of their flight with a small handheld sprayer while we removed their nest they made in the insulation of our pump house. So I though it should work on these nasty stinging wasps too!