Reply #27: Remove all food/scent attractants from the area, including pet food [View All]

[Whoa_Nelly]

and use one of those Wasp Traps you can get at most hardware stores. Set it underneath or beside the window. If you can, seal off that room for a couple of days. Once you think you've got most or all of the colony, use a plastic bag to take down the nest and seal it tightly.
Move quickly to get it outside and put in trash bin. Then, wash the area where the nest was with bleach water (about 2-5 drops of bleach in a spray bottle of water)to remove the scent of the nest area so others don't return to rebuild.

Here's the conundrum: To begin with, how did the wasps get inside, and how are they leaving and returning? Wasps need to go outside to get water and food. If they are stuck indoors, they can get very frustrated and are more prone to attack.

http://counties.cce.cornell.edu/suffolk/grownet/insect-pests/wasps.htm
<snip>
If large numbers enter a building, a commercial wasp and hornet spray or a spray for indoor flying insects may be used. Caution: insects trapped indoors may be irritated and can sting.