In order to eliminate boxelder bugs, you will need to understand a number of biological facts about these insects. Boxelder trees, ash and maple serve as food for boxelder bugs and a fully grown bug can fly distances of over a mile to find protection from cold climates. Furthermore, boxelder bugs prefer living inside the walls and other relatively warm indoor spaces.
The best method to eliminate boxelder bugs is not to let them enter into your home in the first place. This can be accomplished by sealing shut various openings into your home. Replace the window and door screens with new ones if required. Consider installing door sweeps in order to prevent boxelder bugs from finding way into your home from underneath the doors.
Spray insecticides in your home. Bifenthrin, cyfluthrin, deltamethrin, and permethrin are some of the active ingredients found in insecticides. These active ingredients are good enough to instantly kill boxelder bugs. However, insecticides should be used as a last resort, because they can be harmful for human beings as well. Instead of spraying the whole room, spray only spots where boxelder bugs congregate.
Be sure to kill boxelder bugs which come out of hiding. Use a broom and dust pan or a vacuum cleaner to get rid of them. This method is much safe as compared to using an insecticide.
However, there is no way you will be able to eliminate all the bugs this way because these bugs only seldom leave their shelter.
If there are any boxelder, maple, and ash trees in your backyard, you might have to cut them down before you will be able to completely eliminate boxelder bugs. However, this is a drastic measure and should only be relied upon as a last resort.