Your mouth guard needs to be thoroughly cleaned and dried after use to prevent bacterial growth. As soon as you take it out of your mouth, rinse it with cool water and brush it with your toothbrush and toothpaste.
Once a week soak it for a few hours in a mix of water and a mouth guard cleaner such as Ortho Clean or a denture cleaner such as Efferdent. Cleaners will not only remove any plaque and bacteria but will make your guard smell nice.
Avoid makeshift cleaners such as vinegar, hydrogen peroxide or similar, as their odor will penetrate the plastic and will linger for a long time. Rinse and dry your guard and keep it in its own ventilated box and make sure it is stored away from any heat source.
Heat might make it lose its shape.
