What can I do if my insole gets moldy?

Well, it would totally depend on the age of the insole if it would have to be replaced. If it is not very old then it can be easily cleaned by following an easy step. First, clean the easily visible mold with a brush. Afterward, take white vinegar in water and clean the badly affected areas. Once you are done, wipe the liquid with a clean and dry cloth.

Disinfect any moldy insole by spraying it with rubbing alcohol, hydrogen peroxide, or white vinegar. Likewise, you can deodorize by submerging it in baking soda or remove any mold stains by scrubbing insoles with soap and water. However, you can replace if it's already defaced by wear and tear.

Removing the insoles from the shoes and giving them a good clean will help reduce mold build-up. Scrubbing the insoles or putting them in the washing machine should clear the mold from them. A combination of white wine vinegar and baking soda for scrubbing may assist you in odor control and mold build-up. Be sure to take out your insoles and let them dry after cleaning them or after they've gotten wet/damp while wearing them. Dampness is a perfect environment for mold to grow. 

Should you not be able to remove the mold from the insoles, new insoles should be considered. Should mold come back after cleaning the insoles thoroughly, new ones can also be considered.

You can clean your mouldy insole by spraying it with rubbing alcohol, hydrogen peroxide, or white vinegar or scrubbing it with soap and water. If that isn't enough, you can submerge it in baking soda. You should only consider replacing the insole if it already shows signs of wear and tear.