Shoes wear out faster than any other clothing item people wear daily. In constant contact with the ground, the sole of a shoe is subject to all sorts of harsh treatment. Rubber shoe soles can wear down from high traffic use. They are also susceptible to damage from being exposed to heat. Hot summer concrete or the floor of a car can erode the structure of the rubber material. Shoe soles are simple to replace and the effort is less costly than purchasing a new pair.
Clean the soles of the shoes with warm water to remove any dirt or debris. Allow them to dry.
Rub the bottom of the soles of the shoe with the file or the rasp. This will increase adhesion to the new sole.
Coat the bottom of the old shoe sole with the flexible shoe-repair adhesive. Coat the top of the new rubber sole with flexible shoe-repair adhesive. Position the two pieces correctly, then press the new rubber sole onto the old shoe sole.
Put the shoes on and walk around. This bonds the new rubber sole to the shoe.
Trim off any excess rubber around the sole with the utility knife. Smooth the edges with the file or rasp.
Rubber soles can be purchased online in different shapes and sizes from shoe manufacturers. Be sure to purchase the correct size for the shoes you are going to resole. If the old shoe soles are damaged, or torn away from the insoles, simply cut them off with the utility knife. Using the same technique above, bond the new rubber sole to the insoles.