This stuff works. Really. And it's fairly safe for a pesticide - you can spray (or puff it rather) into wall sockets etc.. We have used it for paper wasps where we couldn't get to the nest - after using two other method, we finally found this and it took one try. I recommend Drione over the Delta Dust based upon my research and our experience with Drione.
Amazon.com : 1 LB Drione Pest Insecticide Dust w/...
Specific directions on the Brown Recluse
How To Get Rid of Brown Recluse Spiders How to Get Rid of Brown Recluse Spiders | PestMall Blog Chemical Treatments for Brown Recluse Spiders Dust Applications: The Brown Recluse spider isn't called a recluse for nothing. This spider prefers the secretive habitat of cracks and wall voids much more often than an indiscrete corner. Therefore, most of the treatments you will do for brown recluse spiders will involve a residual dust agent (we recommend
Delta Dust Insecticide or
Drione Dust) puffed into cracks and crevices, wall voids, behind outlet covers and switch plates, and underneath insulation. This is best done with a professional
Hand Duster (Read our
article on proper dusting techniques).
Video on how to use it: