There are many natural products, most of which you probably already have around your home, that can be used for deodorizing smelly sneakers, boots or shoes. All of these shoe deodorizer products should be put on at night and allowed to sit in the shoe overnight for best results.
Sprinkle a layer of baking soda into each shoe when you take them off at night. Allow the baking soda to sit inside the shoes and absorb the moisture and odor overnight and then dump the baking soda into the trash in the morning.
Brew a cup of black tea and allow the tea to cool. Put the cooled tea into a spray bottle and spray the inside of each shoe. Tannin, found in black tea, is a great deodorizer.
Mix one teaspoon of your favorite scent of essential oil with one cup of water. Put the mixture into a spray bottle and spritz the inside of your shoes nightly.
Combine six tablespoons of cornstarch with five drops of lemon oil. Put one tablespoon of the mixture inside each shoe and rub it into the sole. Allow it to sit overnight and then brush it out in the morning.
Use cedar shoe trees inside your shoes or place a piece of cedar wood into each one when you take them off at night. Cedar absorbs moisture and odor out of the shoes. It is also a good idea to store shoes and boots in cedar boxes. Cedar will absorb winter salt from the outside of your shoes.