Baking soda is a great way to destinkify your shoes. It's a tried and tested method to not just get rid of bad odor but also add a nice scent to your shoes. All you need is a few tablespoons of baking soda, a coffee filter, and a rubber band to get the job done. Fill two coffee filters with baking soda and tie them up with the rubber band. You can also add a few essential oils for added scent. Place the small bags in the shoes overnight. This should absorb the moisture and get rid of most of the smell.
If you're looking to get rid of odor without using any type of equipment, you can simply put your shoes in direct sunlight. Untie the shoelaces and try to expose as much of the interior as you can. The sunlight will dry up the moisture and get rid of all that stinky smell. However, it's not as effective as baking soda or other oils. It might not be able to get rid of the bad smell and may take a few days to show any sort of effect.