Wear white and they won't see you. If you do find a nest, don't touch it. The bugs from hell can smell it on you and your gloves.
When I do find a nest, I get the client to pay extra for me to remove it. (75 plus tax)
I go in the evening when the wasps or hornets are all mostly in the nest.
And I watch them for a while.
I count how many sentries there are. On average, there are a couple that will stay on the exterior of the nest guarding it, and up to seven fly back and forth every few minutes.
I have to time my attack in between sentry missions.
I use two types of spray that you can get any-where. One is a liquid that will spray about twenty feet. The other is a foam.
You can't get scared. They can sense it. Have an escape plan worked out in your head and be ready to run like crazy if you have to.
With one hand I spray the heck out of the entrance hole with the liquid spray, and keep spraying. They will start coming out of the hole, so you have to keep spraying them from a distance and keep washing into the hole. It's like a fire hose being spraying on a rioting crowd.
At the same time, you have to coordinate an exterior attack with the foam. Hit the bugs that are walking on the outside of the nest first and then coat the nest.
So, with one hand I am continuing to spray the hole and with the other I am spraying to cover the outside of the nest. The whole time I am watching to see what every one of those bugs from hell is doing.
Then I run like crazy and monitor from a distance...... and go back in a bit and spray any of the crazies that are crawling on the ground towards me, trying to kill me.
When I'm sure it's safe and without touching the nest, I snip the branch it's attached to and put it into a plastic bag and stomp on it for fun. I love the way it squishes under my boots.
If you don't know where they are coming from, use a long shaft hedge saw and just do a quick touch-up from a distance. Those bugs will be gone in September and you can do a better job then. Have fun!