Silverfish are difficult to get a handle on. The feed on paper, bookbinding glue and other types of cellulose & natural fibers. They tend to stay close to their food source but are often found in kitchens/bathrooms when they need water.  They thrive in humidity.  They can live in envelopes, eating the glue, making it unfeasible for pest control technicians to treat.  However, if you have stored boxes, you can dust the interior of the boxes with boric acid or diatomaceous earth.  Your pest control technician can treat cracks and crevices with a variety of natural powders that will help keep the population down.

Silverfish
Silverfish