If you regularly use a thermos or a reusable water bottle you know they can be a pain to clean. The easiest and best way to do this is by shaking 1/8 of a cup of baking soda mixed with 1/2 quart of water inside the bottle. Rinse and wipe dry! Done! The baking soda loosens any residue and rids odors. Your bottle will be clean and fresh for the next fill up.