How To Clean A Coffee Thermos? Step-By-Step

Are you wondering how to cleancoffee thermos that is covered in stains? Take a look at the helpful step-by-step guide below!

How To Clean A Coffee Thermos
It is very necessary to clean your coffee thermos at all times

If you are anything like me, you cannot live without your coffee. So, I work hard to make sure I always have access to my favorite morning beverage

I also do not want to drink coffee out of a dirty coffee pot or coffee thermos. I was having a hard time cleaning my coffee thermos until I discovered how well this step-by-step cleaning method works. Take a look at a few helpful cleaning tips for coffee drinkers below! 

Materials Needed To Clean Your Coffee Travel Mug

woman sitting and holding a coffee thermos
You can easily clean your coffee thermos with just a few materials in your house

To clean your coffee thermos, you will need: 

  • Vinegar
  • Baking soda
  • Salt
  • Ice
  • Hot water
  • A bottle brush, often used to clean a water bottle (can be found on Amazon)
  • Your coffee thermos

Once you have all the necessary items, proceed to the first step below. 

Step 1: Pour Vinegar And Baking Soda Into Your Stainless Steel Coffee Thermos

First, take half of a cup of white vinegar and pour this into your coffee thermos. Then, add one tablespoon of baking soda. Shake the baking soda over the vinegar, which should cause the mixture to froth.

Do not use bleach, as this could lead to a dangerous reaction. The ingredients listed above are already sufficient for cleaning your thermos. 

Step 2: Fill Your Stainless Steel Thermos With Hot Water

Once the fizzing has stopped, fill your coffee thermos the rest of the way with hot water. Your coffee thermos should be completely full. Avoid boiling water, as this could damage your coffee thermos.

Step 3: Let The Substances Dissolve In Your Coffee Mug

The mixture of baking soda and vinegar is reactive. Therefore, do not put the lid back on your coffee thermos, as the increase in pressure could cause your coffee thermos to explode. 

Allow your mixture to dissolve the stains from the inside of your coffee thermos for approximately 10 minutes. 

Step 4: Brush And Rinse Your Coffee Thermos

After you have allowed the mixture to sit for several minutes, take a bottle brush and scrub the inside of your coffee thermos thoroughly, including the spout. After this, dump the mixture into the sink. 

Step 5: Fill Your Thermosflask With Crushed Ice Or Ice Cubes

You need to get the vinegar, baking soda, and any lingering stains off of your coffee thermos. You can do this by filling your coffee thermos with crushed ice or ice cubes approximately a quarter of the way to the top. 

Step 6: Add Two Or Three Tablespoons Of Salt To The Ice

Next, add approximately 2 or 3 tablespoons of salt on top of your ice cubes. Do this as quickly as possible, as your ice cubes may otherwise melt. Larger grain salt, such as kosher salt or sea salt, tends to work the best. 

Step 7: Shake Your Coffee Thermos To Knock Off The Coffee Stains With The Ice And Salt

After adding salt to the ice, secure the lid on your coffee thermos tightly. Then, shake your coffee thermos as hard as possible. The combination of salt and ice should exfoliate whatever is left inside your coffee thermos without causing any damage. 

Step 8: Empty Your Coffee Thermos And Rinse It Well

After your arm gets tired, take the lid off your coffee thermos. Swish the mixture around to loosen any coffee stain grime that might have sunk to the bottom of the thermos. 

Dump the mixture into the sink. Rinse your coffee thermos thoroughly with warm water to remove any residual materials that may be left. 

Step 9: Run Your Coffee Thermos Through Your Normal Cleaning Process

a hand rinsing out coffee inside the coffee thermos
Clean your coffee thermos using your own cleaning process

Finally, you should run your coffee thermos through whatever cleaning process you usually follow. This will remove any vinegar, baking soda, or salt from the inside of your coffee thermos.

If you use dishwasher powder, dish soap, or dishwasher detergent, use that to wash your coffee thermos one more time. If you typically use lemon juice, use that instead. If you have a small coffee thermos, then soapy water might be enough to remove the cleaning ingredients from your coffee thermos.

After you have cleaned your thermos one final time, allow it to dry naturally. 

Final Word On How To Clean A Coffee Thermos

You should clean your coffee thermos thoroughly after each use; however, there are some situations where residual stains can become difficult to remove. In that situation, use the step-by-step guide to clean your coffee thermos thoroughly.

Do not forget to put your coffee thermos through one final wash even after you have used vinegar, baking soda, salt, and ice. If you omit the last cleaning step, you may notice a nasty aftertaste the next time you go to use your coffee thermos. If you use this cleaning process approximately once per month, you should keep your coffee thermos clean.

FAQs About How To Clean A Coffee Thermos

Is it okay if the baking soda and vinegar mixture begins to fizz after I put it into my coffee thermos? 

Yes, the mixture is supposed to do this after you mix the ingredients together in your coffee thermos. The fizzing chemical reaction is important for removing stains and build up from the inside of your coffee thermos. 

Why do I need to add salt to the ice cubes after I add them to the coffee thermos? 

Salt is important for helping the ice cubes exfoliate the inside of your coffee thermos. It can also prevent the ice cubes from melting, which would otherwise remove the cleaning power of the ice cubes themselves.

How often do I need to clean my coffee thermos? 

You should clean your coffee thermos thoroughly after each use. This may not be enough to get all the coffee stains off from the inside of your coffee thermos. That is why you need to use this deeper cleaning and rinsing process from time to time.



  • David R

    Job experience includes extensive work as a teaching assistant, tutor, and guest lecturer and extensive employment in the healthcare field. Have published multiple research papers and numerous poster presentations on various healthcare research topics. Find David on WriterAccess.