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Coffee Tips

How to Clean a Coffee Thermos?

A coffee thermos is a great place to store your hot beverage. It keeps your brew at just the right temperature for you to enjoy your drink when you desire. Besides, it’s portable, helping you enjoy your brew just the way you like it regardless of where you are. But to get your favorite brew fresh any time as was made, it’s important to know how to clean a coffee thermos and how to remove stains that may occur. For many people, cleaning a coffee thermos is not straightforward; the specific shape and design of most coffee thermos don’t make this any better.

pouring coffee from the coffee thermos

Fortunately, few methods work well to keep your coffee thermos free of stain and unpleasant smell. This article outlines the various methods you can use to clean your coffee container removing all stains or preventing them from occurring.

Let’s get started.

Everyday cleaning routine

As a general care rule, you should never let your coffee thermos sit with your drink the whole day. You must clean it after a day holding the drink. But this general care takes more than your hand and the washing cloth; and no, just a rinse with water is not enough. Instead, use this;


What you need

  • Bottle scrubber
  • Microfiber or dishcloth
  • Mild dish detergent
  • Soft kitchen towel



  1. Add warm water mixed with dish detergent to fill your thermos. Ensure you avoid submerging your thermos in water; fill it using a container instead.
  2. Leave the mixture for three to five minutes to remove any crud
  3. Use your bottle scrubber wrapped with a dish or microfiber cloth to gently scrub inside the container. To remove any stuck elements, scrub using the bottle scrubber alone.
  4. Pour your mixture and rinse with warm water
  5. Use your towel to wipe the inside
  6. Store in a dry place to allow for air drying


Apart from the general care, you may need extra effort to remove stains from your coffee thermos.


Remove stains from a coffee thermos

Baking soda and vinegar or peroxide method

What you need

  • ½ cup vinegar or peroxide
  • Two tablespoons baking soda
  • Hot water
  • Towel



  1. Place your thermos in the sink
  2. Pour vinegar or peroxide and baking soda into your thermos and shake gently to allow for the two to mix and react gradually.
  3. Wait till the fizzing and frothing subside, then fill the thermos with hot water.
  4. Leave the mixture (for approximately 10 minutes) to dissolve the coffee stain. Do not lid the thermos as the reaction can extensively react to overflow (this is why the thermos needs to be in the sink).
  5. Use the bottle brush to thoroughly clean the inside of the thermos.
  6. Empty the solution and rinse the thermos several times. You don’t want vinegar and baking soda residue to remain or the thermos to retain the mixture smell.
  7. Wipe your thermos with your towel and store it to air dry.


Salt and ice method

This method may be new to you, but it works wonders.


What you need

  • Ice (crushed or in cube form)
  • 2-3 tablespoons of salt (the coarser the grain, the better—consider salts such as sea salt or coarse-ground salt)



  1. Put crushed ice cubes to fill a quarter of your thermos
  2. Pour 2-3 tablespoons of salt
  3. Fit in your lid and shake the thermos well. The salt and the ice remove any stains without causing damage to the flask.
  4. Pour the mixture and fill the thermos with warm water (shake as you do this to remove any salt and ice left).
  5. Rinse the flask several times
  6. Use a towel to dry any water and leave it to dry in the air.


Dishwasher powder method

Dishwasher powder is one of the most effective cleaning materials for removing coffee stains. The powder works better than liquid because of its coarseness.


What you need

  • A tablespoon of dishwasher powder per quart of what the thermos can hold



  1. Put your dishwasher powder into your flask and pour hot water into it. Do not fill the water
  2. Secure the lid of the thermos and shake briefly
  3. Add hot water (the hotter, the better) to fill the thermos to the brim and leave the thermos to soak for a few hours (preferably overnight). This time around, leave the thermos without the lid
  4. Pour out half of the liquid and scrub the inside using the bottle scrubber
  5. Empty and rinse several times
  6. Leave it to air dry


Denture tablet method

Denture tablets can be the solution to the most stubborn coffee thermos stains.


What you need

  • 1-2 denture tablets
  • Warm or hot water



  1. Pour the water to fill half the thermos. Leave to soak for a while before putting the tablets. For the denture to be effective on all areas of the thermos inside, ensure you swirl the thermos to wet all the inside
  2. Put 1-2 tablets in the thermos. Ensure the flask is in the sink as the tablets cause a chemical reaction that may lead to the overflowing of the solution
  3. Leave for about 30 minutes and secure the lid
  4. Allow it to sit for several hours (can be overnight). Scrub gently using a bottle scrubber
  5. Dump the thermos and rinse thoroughly
  6. Dry using a towel and allow it to air dry


Lemon juice

If you’re looking for an easy and safe way to eliminate build-up stains from the coffee thermos, lemon juice can work best. The solution is a natural descaling solution for everyday use.


What you need

  • Lemon juice
  • Warm water



  1. Mix lemon juice and water in equal measure and pour it into your thermos
  2. Let the mixture sit for 5–10 minutes before scrubbing with a bottle scrubber
  3. Dump the thermos and rinse several times to get rid of the lemon scent
  4. Let your thermos air dry


Taking care of your thermos

The best and easiest way to prevent the build-up of stubborn coffee stains that are much harder to clean is to clean your thermos every day. In doing so, use gentle materials and handle them with care.

Never wash the thermos in the dishwasher; otherwise, the abrasive washing process may destroy it.

Avoid using bleach as it can be hazardous. Besides, abrasives such as Comet may scratch the thermos, so avoid them.

Because of its everyday use and its construction, your coffee thermos can develop stains. Removing the resistant strains doesn’t have to be expensive and difficult. You can quickly use one of the methods depending on what’s available to you.


Related Articles

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How to Eliminate Coffee Stains From Your Thermos?