How to Clean a Thermos

Jacob said, “How . . . do you clean the bottom of a coffee thermos?”

You Will Need:

• Dish liquid
• Water
• Baking soda
• A bottle brush
• Rice
• White vinegar
• Denture tablets or antacid tablets
• Salt

Steps to Clean the Thermos:

1. For regular cleaning, squirt some dish liquid into the thermos and add water. Attach the top, then shake the bottle. Pour the solution out through the spout if applicable, then repeat with plain water to rinse.¹
2. If there is any residue in the thermos, pour about ¼ cup of baking soda into the thermos, then fill it with water and stir to mix. Let the baking soda solution sit in the thermos overnight.²
3. For very dirty thermos interiors, use a bottle brush to scrub off the residue.² However, do not use a bottle brush if the thermos is glass as it could crack.³
4. If you don’t have a bottle brush, use rice. Partially fill the thermos with water, then add about ¼ cup of white vinegar. Pour in some dry rice, cap the thermos, and shake it well to clean off any residue.²
5. To rid your thermos of mineral deposits, use denture tablets² or antacid tablets.⁴ Fill the thermos with water, then drop a tablet into the water. Leave the solution in the thermos until the fizzing stops.²
6. If your thermos smells, pour about ¼ cup of dry salt into it. Let the salt sit in the thermos for a couple days, then rinse it out.⁵
7. Dry the thermos upside-down.³

• Don’t put any kind of thermos in a dishwasher.³
• Do not submerge the thermos in water, as the water could get between the liner and bottle.³
• Never use chlorine bleach to clean a stainless steel thermos, as the bleach can damage the steel weld.¹
• If you plan on putting away the thermos for the warmer months, put a whole clove in it to prevent it from smelling musty when you bring it back out from storage. If you don’t have a clove, put a teaspoon of salt inside instead.²

1. The Cleaning Encyclopedia by Don Aslett
2. Extraordinary Uses for Ordinary Things by Reader’s Digest
3. Clean it Fast, Clean it RIGHT by Jeff Bredenberg
4. 99 Cent Solutions by Reader’s Digest
5. Haley’s Cleaning Hints by Graham and Rosemary Haley