Wayne-
One word of caution before you use "chemicals"...
A number of years ago we had a section of our aluminum soffit pop out of the track from a strong storm. It got pushed UPWARD and left a gap that wasps immediately took up as "home".
As luck would have it, this new wasp home was at the highest portion of the house. Right above the back "walk-out" section, 2 stories high.
I borrowed a friend's L-O-N-G extension ladder, grabbed a cheap can of "wasp be gone" and climbed up the ladder. As I got to the top (man, that was HIGH up there!) I realized that I'd have to be just below the nest, shooting the wasp-killer through the rungs of the ladder, up into the soffit opening.
My palms are beginning to sweat, my legs are starting to quiver, so I figured I'd better "git er done" as quickly as possible, so I point the can and shoot...
Unknown to me, there was a small sliver of plastic on the spray head of the can hanging directly in front of the nozzle that was somehow a remnant of the manufacturing process. Instead of a nice solid "jet" of chemical that was supposed to hit the nest, I got a fog of fine mist that CAME BACK AT ME! In the last nano-second of spray, the plastic sliver dislodged and a small part of chemical hit the nest, but by that time my aim was all off as I was in a chemical soup-cloud that was burning my eyes and lungs. When the last bit of chemical-jet tapped the nest, 100's of wasps came out to see WHO was there!
Picture me trying to quickly climb back down the ladder with a nest full of wasps buzzing around my head all of the while, choking and gasping for air...
Needless to say, I ALWAYS check the condiditon of the spray-can nozzle before climbing a ladder!