How to Clean a Coffee Thermos

Do you not know how to wash the thermos inside from tea and coffee plaque, scale, mould? We tell you how to do it correctly:

  • How to get rid of dirt.
  • What can be cleaned?
  • What can not be done is not to damage the product.


Types of pollution

Over time, there is a persistent plaque from your favourite drink or mould on your brand new thermos. This is not pleasing to the eye and is harmful to health. Why is this happening?

Tea and coffee plaque

A cup of hot drink pleasantly warms in the cold. But with the constant use of a thermos, an unpleasant brown film appears inside. It is formed due to caffeine and essential oils.


Hard water and insufficient care lead to the appearance of limescale inside the thermos. It may contain deposits of chlorine, heavy metals, bacteria, so it is better to clean it.

Mould (fungus)

Sometimes with prolonged storage of dishes in a closed form, mould starts. Significantly often, the fungus appears when a still wet thermos is clogged.

Mould has an unpleasant appearance and smell, spoils the taste of drinks and food. It can cause an allergic reaction and poisoning, so you need to get rid of it.

Cleaning methods

Particular drugs can be used to clean the thermos. There are quite a few of them. But you can also use improvised means, which are convenient to wash the thermal course at home.

Baking soda

Easily clean the flask of scale, plaque, and at the same time disinfect. A proven inexpensive tool that copes even with mould.

Add soda to hot water. Pour 1 tsp., 3 tbsp. l. or even more: it all depends on the degree of contamination. Stand for 6-8 hours. Then rinse the thermos.


Removes plaque, stains, plus eliminates the odour. You will need 8 tbsp. L salt per 1 litre of hot water. Some make a more concentrated saline solution. The saline solution is left for 6-8 hours, after which the product is washed.

Mustard powder

The recipe is simple: 2-5 tbsp. L powder is mixed in a dish with hot water, closed, shaken and kept for 4-8 hours, washed.

Lemon, citric acid

Effectively clean the flask from brewing and coffee plaque. Citrus is cut into slices, placed in a dish and poured with boiling water. They wait a few hours and wash the thermos.

Instead of lemon, you can take 2 tsp—citric acid. With severe contamination, put 2 tbsp—l substances. After 3-8 hours, wash the dishes.


An aqueous solution with food vinegar helps to wash the flask from tea and scale. Take a third of vinegar and two-thirds of hot water, pour into a flask. After 2-6 hours, the product with dish gel is washed correctly.

If you add a little baking soda to the vinegar, then everything will be cleared very quickly.

Baking powder or baking powder

They usually include soda and citric acid, which help remove scale and wash the plaque inside the thermos. You need to take 2-3 tbsp. l. or 1-2 sachets of substance, mix with warm water in thermal treatment, leave for 2-3 hours, and then rinse the product.

Rice or pearl barley

They have cleansing properties. It is enough to pour a few tablespoons of rice or barley into a flask and pour boiling water. It is advisable to shake the thermos 3-4 times per hour. Then close, shake and leave for a couple of hours. It remains only to rinse the dishes.

Even better, the recipe works with the addition of 1-2 tsp. Soda.

Soda water

Successfully fights plaque from coffee and after tea. Use “Pepsi”, “Fanta”, “Sprite”. Coca-Cola is especially praised.

However, to store soda in a thermos, manufacturers of dishes do not recommend: due to a large amount of carbon dioxide, the surface of the flask can deteriorate. Therefore, it is undesirable to keep a carbonated drink for longer than 20 minutes.

Do not close the lid so that the cork does not fly out or the glass bulb is not damaged.

Another recipe: boil the soda to get the gas out and then pour it into the dishes. Stand for a few hours, then wash.

Ammonia solution

Prolonged exposure to ammonia on the steel flask will damage it. Plus, the ammonia solution will control the rubber pads and leave an unpleasant odour.

But you can occasionally wipe the flask with ammonia or use an aqueous solution. To prepare the solution, 5-10 drops of the substance are added to each litre of liquid, stirred and briefly left in the flask. After cleaning, the dishes are thoroughly washed.

Medical alcohol

Pour the flask for a third of alcohol. Add warm water. Close and shake well. Leave for 45-60 minutes. Then rinse.

The recipe can be used no more than 3-4 times a year not to spoil the flask.

Gel for dishes, laundry soap

A simple but effective solution. The products will remove greasy spots, fight mould and plaque.

Dishwasher detergent

Special tablets and gel are potent agents. Cope with the black coating from drinks and fungus. After cleaning the dishes, wash them with dish gel and pour boiling water several times.

Before use, read the instructions and make sure that the selected drug is suitable for your dishes.

Tooth powder or paste

Suitable for cleaning stainless steel flasks. Wipe it with a soft sponge or rag. Then rinse with water.

Tablet “Korea”

Tablets for cleaning dentures perfectly clean the thermos inside. They remove even a persistent plaque from drinks or lime.

Use warm water: it should not be too hot. Keep the solution in a dish for 6-8 hours, then rinse. You will need 1-2 tablets, and with severe contamination – more.

Do not pour water to the very top of the bulb so that the resulting foam does not run out over the edge. Or carry out the procedure in the sink.

Hydrogen peroxide with soda

Take 100 g of soda and use peroxide to make a gruel. Gently wipe the flask with it, leave it to stand for a while and rinse.

Unique means of scale and plaque

To clean stainless steel dishes, specially designed for this purpose, means are used:

  • “Silit”;
  • Antinakipin;
  • “Glitter of Steel”;
  • “Dafoe”.

They clean the flask well from plaque and mould. Any drug of your choice is poured with boiling water and left in a thermos for an average of 1 hour. Then wash the dishes.

What not to use

To not spoil the thermos flask, you can not use rough cleaning methods that will leave scratches or damage the inner surface. After all, damage incapacitates the thermal dishes. Here’s what’s not suitable for cleaning:

  • iron washcloths for words;
  • hard brushes;
  • abrasive detergents;
  • sand;
  • crushed eggshells;
  • aggressive chemistry.

What’s right? Soft brush, sponge, rag, detergents of delicate action – particular and improvised.

Nuances of washing different parts of the thermos

After each use, it is necessary to wash the thermos immediately. Moreover, it would help if you passed it correctly, that is, all its parts – a flask, a lid, a cork. Then it is necessary to dry all the details, and only after removing them for storage: this will prevent the appearance of mould.


When caring for a thermos, you should consider the features of the material from which the flask is made. Then the dishes will last longer.

Metal, stainless steel

Such flasks are durable, hold heat well. But scratches quickly appear on them.

Metal flasks can withstand different methods of cleaning but are not rough abrasive. Here’s what’s for you:

  • lemon;
  • citric acid;
  • baking soda;
  • vinegar;
  • baking powder for dough;
  • bakery powder;
  • rice;
  • barley;
  • soda;
  • “Coca-Cola” (with caution);
  • tablets of the “Korea” type.


Perfectly keeps warm, but at the same time fragile. Therefore, washing with a glass bulb should be handled especially carefully: not to break it, you need to clean it without unnecessary mechanical effort.

When cleaning, use peaceful means:

  • lemon;
  • citric acid;
  • vinegar (preferably apple);
  • carbonated drinks;
  • saline solution;
  • mustard;
  • gel for washing dishes.

Teflon coated

Metal flasks with Teflon coating are similar in their characteristics to steel. They are not subject to cleaning with abrasives, as well as aggressive chemistry. Other methods of washing will do.

Cover (regular and with button), cork

These parts of the thermos also require mandatory care. After all, they also accumulate particles of products that need to be cleaned.

The button cover is washed in the “open” position. Plus, do not close during drying.

After drying, you do not need to seal the thermos lid tightly: it is better to keep the thermos open or with little air access to the flask. This will prevent mould from appearing.

Narrow neck

A thermos with a narrow throat is not always easy to wash off the black plaque inside. But there are ways. It can be cleaned even without a brush.

To begin with, you can pour the flask with hot water to the top and let it stand. Then you can apply the above method of cleaning with citric acid, soda, cereals, mustard. It will take some time to shake the thermos to clean the adhering particles of products or plaque mechanically.

Can I wash in the dishwasher?

Thermos is suitable only for a delicate manual wash. Many are interested in why it can not be washed in the dishwasher. The answer is simple: the thermal cooking will deteriorate.

When washing in the dishwasher, the thermos is in hot water for a long time. From this, the insulating material fails, so the dishes cease to hold heat. And if water falls between the body and the bulb, there is a needy smell of dampness.

Thermos also cannot be used in microwave ovens. Plus, leave near the fire and heating devices.

How to treat a new thermos

After buying a new thermos, you should not immediately fill it with a drink or food. Before the first use, the product should be washed thoroughly. So you will remove from it possible traces of factory technical lubricant, household contaminants and germs so that they do not get into food.

It’s easy to do. It is enough to wash the thermos with warm water with gel for dishes. Then dry. Additionally, you can dive the product with boiling water.

Each time before using a thermos, especially with a glass bulb, it should be prepared: pour hot or cold water for 2-3 minutes to heat or cool the flask before use.

Prevention of plaque and mould formation

The best remedy against plaque is prevention. If you regularly correctly care for the thermos, it will last a long time, and unpleasant plaque and mould will not overshadow your mood.

Here are six simple rules to help avoid plaque formation from drinks, hard water and mould:

  1. Wash the thermos entirely after use.
  2. Dry it well disassembled.
  3. Keep it open or with the lid loosely closed.
  4. Do not keep cooked drinks on a thermal sheet for longer than 24 hours.
  5. Use soft water for food and beverages that you plan to put in a thermos.
  6. Brew coffee and tea in a separate dish, and only then pour them into a thermos: this will prevent the formation of a complex plaque.

Now you know proper chips for handling a thermos and more than 15 proven ways to clean it. Try, choose the best!

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