The Jason Markk Moso Bamboo Charcoal Shoe Inserts remove odors, bacteria, pollutants, allergens, mold and mildew from your shoes. Throw them in when you're not wearing them and they'll be completely neutralized in a few days. They're all-natural, completely fragrance free and non-toxic. To recharge them, place them in direct sunlight for one hour, once a month. Each one can be recharged up to twelve times. Use the handy planner printed on the back of each sachet so you know how many times you've recharged them!