How Do You Get Coffee Build Up Out Of A Thermos?
To remove coffee build up from a thermos, fill it with hot water and add a tablespoon of baking soda. Let it sit for an hour before pouring out the mixture and rinsing the thermos thoroughly with warm soapy water. If the build up is stubborn, try using a bottle brush or a mixture of vinegar and baking soda. Make sure to dry the thermos completely before storing it.