Cleaning your thermos should always be done via manufacturer recommendation. While a lot of lids are top-rack, dishwasher safe, the majority of bottles should be washed by hand with soap and warm water and rinsed with hot water after every use, as dishwashers use scalding hot temperatures and abrasive detergents that can ruin the exterior finish of the bottle. If you notice the bottle starting to smell, adding a touch of vinegar to the soap and warm water solution will help to eliminate any mold that may be forming or flavors that have locked into the stainless steel interior.