The SteriShoe® sanitizer is applied to the smelly shoes only. Just like you wash your socks, you need to clean your shoes. The offensive shoe smell is an indication of odor-causing bacteria living in your shoes. The SteriShoe® sanitizer eliminates up to 99.9% of odor causing bacteria in shoes. Sanitizing the inside of your shoes is a great way to provide a cleaner and healthier environment for your feet.