To get rid of silverfish using borax, make a paste out of boric acid, apply it to pieces of card stock or sprinkle the boric acid on crackers, and set the pieces out as bait. Borax packaged for sale does not eliminate pests.
- Make a boric acid paste
Pour the powder form of boric acid and water into a medium mixing bowl, and add enough flour to give the mixture the consistency of paste. Follow the safety instructions on the boric acid packaging when it comes to handling and using the acid.
- Use the acid to make baits and traps
Dip index cards or pieces of card stock into the paste, coating thoroughly. Allow the paste to dry to a tacky consistency, and set the traps where you have seen silverfish. Wait for the silverfish to get stuck on the traps. You can also set a cracker or two in areas where you have seen silverfish, and sprinkle boric acid powder around and on top of the cracker. Make sure children and pets cannot reach the bait.
- Spray crevices where silverfish may be hiding
Mix boric acid powder in water to make a 5 percent solution inside a spray bottle. Use the stream setting to send the mixture deep into crevices in your home where silverfish may be hiding.