It's tempting to toss a pair of smelly sneakers into the washing machine to get them clean and smelling fresh again. But washing sneakers can take a lot of time since the drying process after washing can take hours, if not days. The reality is the odor from smelly sneaks usually comes from the insoles, which are removable and washable on their own. To clean them, just slip them out of the sneaker and wash them with warm water and liquid laundry detergent. Allow them air dry completely before placing back into the sneaker. If they still smell, toss them into a zipper plastic bag and sprinkle baking soda inside. Zip the bag closed and let it sit for 24 hours. This will absorb odors and usually does the trick to make them smell (almost) as good as new.