Bag Your Mattress
Once you’ve vacuumed and chemically treated your mattress and box spring, enclose them in encasement bags. If the bed bugs found a way inside the mattress, the odds are that the spray chemicals did not kill them.
Encasement bags have special zippers that trap the bed bugs and prevent them from escaping. Keep these bags on for at least a year because a fully fed bed bug can live more than 10 months between meals.
If the idea of sleeping on a tiny bed bug cemetery is too much to bear, the only alternative is to toss the mattress and box spring and buy new ones. Just be sure to wrap up the infested one before hauling it through your house, and don’t buy a used mattress!