Bedbugs are parasites that can potentially spread disease. Once you find that you have bedbugs in your home, the next step is to find out where they are staying so that you can get rid of them. One difficulty with this is bedbugs' hatred of light, which makes it difficult to find them during waking hours. Although a black light will not help you spot a bedbug directly, you can use the black light to find the trail the bedbug used.
Remove the bedding from the bed. You will be able to find the trails that the bedbugs leave behind more easily when you have direct access to the mattress.
Turn on the black light and start by looking in the corner seams of the mattress. Follow the light along the mattress seam until you are able to see a glowing trail. The bedbugs will leave a debris trail of their waste and blood.
Follow the debris trail until you are able to find where it ends. If the bedbugs are not in the corner seams of the bed, they may be in a nearby electrical outlet or the seam of the wall. Heat and suffocation are the only ways to kill bedbugs once they are found.