Shoes sometimes acquire mold because they get sweat or water on the surface, and then are stored in a closet--a dark place where mold can grow. If you get mold growth on your shoes, you usually don't need to throw them away. You can try several remedies for mold at home that will restore your shoes.
To get mold off of leather shoes, begin by brushing any visible mold off the shoe with a bristle brush. Do this outside because when you brush mold off of the shoes, the spores will scatter into the air, and you don't want to scatter the spores inside your home. It's also helpful to brush the mold off on a sunny day, because sunny environments discourage mold growth. After all the visible mold is brushed off, make a solution of equal parts rubbing alcohol and water. Use a soft cloth to rub this solution on the area where the mold was growing. Use circular motions, as if polishing the leather. Then wash the area with saddle soap and water. Rinse well to get all of the soap off, then dry the shoes in an open, airy place to discourage further mold growth. Once the leather is dry, you may want to polish the entire shoe with a leather shoe polish because the rubbing alcohol may have stripped the finish. Polish will help protect the shoe from scuffs, scratches and color variations. To finish, spray the inside of the shoe with a specially formulated shoe odor eliminator. This will not encourage or discourage mold growth, but often, mold causes shoes to have a musty odor that lingers even after all the mold spores are gone. This spray will make the shoes smell fresh again.
Shoes that are made out of canvas, rubber and many other materials can also get mold. To remove the mold, begin by removing any visible mold outside with a bristle brush, the same way you would remove visible mold on a leather shoe. Wash the shoe with mild soap and water and let it air dry outside. If this does not eliminate all of the mold, you may have to take another course of action. If the shoes are white, you can rub the moldy spot with lemon juice, coat it with salt, let it dry in the sun and rinse. If the shoes are colored, mix a solution of one tablespoon sodium perborate bleach with one pint water. Test an inconspicuous patch of the shoe by using a cloth to rub the solution on, and then let it dry. If the color has not been compromised, soak the whole shoe in this solution for 30 minutes. Rub the shoes with a towel that has been soaked in distilled vinegar. This will stop the bleaching action. Rinse the shoes well and allow them to dry outside to discourage further mold growth. As with leather shoes, you may want to spray the inside of the shoes with an odor eliminator so the musty mold smell doesn't linger.