In addition, sprays or baits must be targeted at cockroach hiding places to get the greatest effectiveness from a treatment. Mobile, Birmingham, and Auburn-Opelika. The best method for reducing the number of smokybrown cockroaches inside your house is the removal or treatment of cockroach hiding places outside your house. If you reduce the number of cockroaches outside, you will reduce the number of cockroaches inside the house. Sealing up cracks and crevices through which cockroaches enter your house is also important.
Many people employ boric acid dust.
Applied in backs of cabinets and other places where you frequently see cockroaches, it may kill cockroaches faster than the dry air in most houses. Boric acid must remain dry to be effective. If the powder becomes moist it will cake and the dust, which the cockroaches eat when they clean themselves, will not stick to the cockroaches. This quality of boric acid also makes it very poor for outdoor use. Boric acid in contact with moist soil will dissolve and if in high enough concentration could even poison nearby plants.