Dusts

• Two types of abrasive dust, diatomaceous earth and boric acid, can be used to control spiders. Diatomaceous earth works by dehydrating spiders that come in contact with it,killing them within hours. Boric acid works by killing spiders that ingest it. Apply these dusts only to wall voids, attics and other places that are out of the way. Use natural diatomaceous earth, not pool grade, for controlling spider problems.
  
  

Sprays

• You can make your own spray to eliminate spiders in your home by mixing 5 tbsp. of natural liquid soap with 5 tbsp. of citronella oil in 1 qt. of water. Researcher Shawn Bassler at Washington State University reports that this mixture kills spiders on contact. Mixing 1 qt. of 5 percent white distilled vinegar with 1 tsp. of coconut oil also makes an effective spray. Many herbs contain volatile oils that are good insecticides. Oil of clove and nutmeg, for instance, contain eugenol, a fast-acting insecticide for spiders. Volatile oils work as contact insecticides so they may have to be reapplied. The Environmental Protection Agency considers eugenol a minimum risk pesticide that causes minimal or no damage to those using it or to the environment.
  
  

Vacuuming

• The best way to get rid of spiders is to vacuum them up, states the University of Maine Cooperative Extension. Spiders have soft bodies, and the suction from the vacuum cleaner usually kills them. Vacuuming even works better than many pesticide sprays, which aren’t always effective against web-sitting spiders or egg sacs.
  
  

Other Ideas

• Use a strong stream of water to wash spiders and webbing off the outside of buildings. Replace outdoor lighting with yellow or sodium vapor lights to reduce insects that are attracted to lights, eliminating the food available to spiders. Catch spiders with sticky traps used to control cockroaches along baseboards.