You know that wobbly chair leg with the screw that won’t tighten anymore? Here's an easy fix. Remove the screw and insert one or two toothpicks in the hole, along with a dab of wood glue to hold them in place. Once the glue sets, break off the tops of the toothpicks and insert the screw. The extra wood provided by the toothpicks will give the screw threads something to bite into, holding the screw firm.