Tea and coffee can leave unsightly brown stains inside your thermos, but with this simple trick, you can make your favorite thermos look as good as new again.
How to Clean Your Thermos
Add 1-2 tablespoons of baking soda to your thermos.
Fill the thermos with boiling water.
Let the mixture work for at least 30 minutes, but preferably overnight.
Rinse thoroughly with water.
If the stains persist, repeat the process.
Does Your Thermos Smell Bad?
You can use a similar method to remove any sour smells from your thermos. Simply pour 1-2 tablespoons of coarse salt into the thermos and fill it with cold water. For best results, let the thermos sit overnight.
