Locate the part of the attic where the hornets and wasps are coming and going.
Getting rid of wasps in attic.
Leave the shop vac on for a few hours to catch as many of them as you can.
Spray the nest according to the directions on your spray.
Attic is a not so attended place and thus the wasps can live there happily and also make a nest.
If the nest is a hanging nest make sure you purchase a spray with a projectile shot so that you can completely cover the nest with it.
Because they are a dangerous pest i would recommend calling the local orkin branch office and asking them to send over a highly trained orkin pest specialist.
Another very common place to find wasps nesting is in attic spaces.
Getting rid of the nest is a bit difficult as compared to a single wasp but if you take the appropriate measures you will surely be successful.
It is very easy for wasps to get into attics normally due to openings around vents and or poor construction practices that leave big gaps between the sections of wood near the areas where the shingles and gutters meet up.
You need to locate the nest first.
Fill a shop vac with soapy water then place the head attachment near the source of the insects.