If your thermos has become dark inside, covered with plaque and smells like yesterday’s coffee or old tea, do not rush to throw it away. Even the most neglected vessel can be washed without chemicals.
1. Soda and hot water
Pour 2-3 tablespoons of baking soda into a thermos and fill with boiling water to the very top. Cover and leave for 4-6 hours or overnight. In the morning, drain the solution and rinse with warm water. The soda will gently peel off plaque and remove the smell.
2. Vinegar and water
Mix equal parts of table vinegar and warm water. Pour into a thermos, close and leave for 3-4 hours. After this, rinse thoroughly with running water. Vinegar will dissolve limescale and disinfect the surface.
3. Lemon and salt
Squeeze the juice of one lemon into a thermos, add 1 tablespoon of salt and fill with warm water. Leave for 2-3 hours. Citric acid will lighten the walls, and salt will enhance the cleansing effect. Works especially well after herbal teas or berry infusions.
Important Tips:
- Do not use metal brushes as they will scratch the glass flask.
- Rinse the thermos after each use, especially if you have poured milk or sugary drinks.
- Wash the lid and rubber gasket separately too, this is where the smell most often lives.
Remember: even the oldest thermos can last for years if you care for it properly.
