Whatever you spray them with, do it at all creepy and stalker like, at night when they are sleeping and all at the nest.
Raid makes a good, long range spray.
Another good one, I think it's a Raid product as well, is the foaming one for wall nests and such. You spray the foam over their entrance/exit, then insert the red straw that comes with the spray can of death into the nozzle, insert the red tube of death into the nest, and nuke those bastards while they are trapped inside (by the foam you sprayed at step one) and can't escape.
And again at night, all creepy and stalker like, when they are cuddled up sleeping.