Art... It ain't bad if you are not near a nest but if you are near a nest ya gotta be reeeal careful. I have never used a pesticide for hornet nest removal unless it's attached to the house or some othet structure. The best way I have found is to use a metal rod with a cloth soaked with gas... you light the nest on fire and the hornets outside of the nest will dive into it.

As for the nasty predator wasps which build the small nests (one wasp) I find a sledge hammer after dark is humane riddance. I have also used the spray from a garden hose to destoy the nest after seeing the wasp leave and go out of sight. It may take several attempts after they rebuild each time and be quite tedious but it is better than killing them. If it's out of "normal traffic" (I presently have one at the apex of my garage gable end under the eave) I leave em alone. They kill insects in my carrot patch... well, it would be a carrot patch if I could get the carrots to grow.