Oh, stinky hiking shoes. As a mom of 4 boys, I've been there more than I want to remember. For mildly stinky shoes, we sprinkle some baking soda inside, shake them around, and dump them out the next morning. For really stinking kids hiking boots, we throw them in the washing machine (unless they're mostly leather or waterproof). Every shoe I've washed comes out cleaner and smelling good, and always seems to breathe new life into an old pair of kids shoes for hiking.