Spectracide Pro is the best stuff we have ever found, it will knock the little pests right out of the sky if you can hit them. The 47,000 volts is the dielectric rating. It’s supposed to be nonconductive to 47kv, but I don’t plan to test it.I once bought a can of stuff, it was a white and red and black can, I think it was branded "Spectracide" but it also had a line of text in bold that talked about "47,000 volts" or words to that effect. I never understood what "47.000 volts" meant, but it knocked down the orneriest hornets you've ever seen like a shotgun.
I've bought several types/brands of hornet killer since then, but nothing nearly as effective as that stuff was. And it wasn't a foam – more of a very low-viscosity liquid, like alcohol or something.
ETA: Ha! Found it at Home Depot online!
I helped a neighbor do just about that. Nest right over the sidewalk. Went out at night. He had the lid, I had the pole pruner. Dropped it in. Lid on.My pop used to park under the paper nest with an open garbage can in the back of his truck at 3 a.m and pole clip the branch of nest into said can ,throw the lid on it ! As you can imagine he had varying levels of success with this trick.. hahaha.