Cleaning mouthguards is often necessary when odor and bacteria build up within the mouthguard. Luckily, since these are not worn all the time, they can be soaked for a few hours in a homemade solution that will kill bacteria, without damaging or over-drying the mouthguard.
Hydrogen peroxide works as an antibacterial that will clean the mouthguard effectively without causing damage to the finish. In a dish, mix 2 parts warm water to 1 part three percent hydrogen peroxide. This can be purchased at any drug store, and is used for cleaning cuts and scrapes on the body. Soak the mouthguard for a few hours, or overnight when possible, then rinse it with warm water to remove any residue.
Baking soda is the perfect deodorizer for mouthguards. It is a mild cleaning agent that both cleans and disinfects, and is completely safe and natural. In a dish, mix 1 cup warm water with 2 teaspoons of baking soda. Stir the solution until the baking soda has dissolved, then place the mouthguard in the solution. Let it soak for a few hours or overnight, then rinse with warm water.
Bleach is yet another solution that will clean the mouthguard, but the homemade solution should be heavily diluted. In a dish, mix 1 part bleach to 10 parts water. Soak the mouthguard in the solution for a brief 20 to 30 minutes, then rinse thoroughly with warm water to remove any remaining residue. Keep in mind that bleach should not be ingested, so it is strongly recommended that you rinse the mouthguard thoroughly, then go over the mouthguard with a rubbing of toothpaste to remove any remaining bleach residue. Simply dab a little toothpaste onto the mouthguard, and rub your fingertips over the entire guard. Do not use a toothbrush, as this can scratch the finish of the mouthguard.
Also note that bleach can sometimes cause discoloration, so test a small area of the mouthguard by dipping just a small corner of the mouthguard in the solution for 20 minutes.