Since typical Powder Post Beetle infestation begins with bringing in infested wood or wooden piece of furnishing, so inspect these for the beetle exit holes.

Powderpost beetles will only lay their eggs on bare, unfinished wood. Wood which is painted, varnished, waxed or similarly sealed is generally safe from attack provided no unfinished surfaces are exposed. Bare wood can be protected from attack by painting or finishing exposed surfaces. Beetles emerging from finished articles such as furniture were usually in the wood before the finish was applied. (Note: beetles emerging from finished wood can, however, reinfest by laying eggs in their own exit holes; sealing the holes prevents this possibility).

However, if the situation is out of hand or does not improve by your efforts or if you have a low tolerance of Carpet Beetles, your only choice may be to have a professional Moths extermination service.