Ideas to Help Get Rid of Different Stains out Your Thermos

There is no question that a thermos is really handy especially in the cold season when a cup of tea or coffee does more than just quench thirst. The stains in the thermos tend to add a stale taste of coffee or tea to any other drink you put in the thermos.

The problem comes in when you have to clean the thermos and take the stains out to remove that stale taste. These thermoses tend to get stains due to them always being filled with coffee or other hot drinks and getting to the bottom of the thermos is tough due to the way it is made. Despite rinsing the thermos with soap and water thoroughly on the inside, deposits will still start gathering over a period of time. Before you know it, your thermos retains a musky scent and will be unpleasant when you open it. A basic clean using a brush with soap and water may do the trick sometimes but most of the time it won’t help. There are a few different ways in which you can clean it thoroughly and we will be going through some of them.


Use a Tea Bag

This may seem ridiculous but using a tea bag actually works. The tea and sugar granules are the main cause of stains. Take a tea bag and put it in the thermos then fill the thermos with boiling water. Close the thermos, make sure the lid is tightly secured and leave it till the following day. Empty out the thermos and use a stainless-steel wire to remove the last bit of stain rings completely. Then rinse and turn with the opening facing downwards to drain and dry.


Baking Soda or Bicarbonate of Soda

Take the thermos and put in three teaspoons of baking soda and fill with boiling water.

The mixture should be left for about 30minutes before it’s rinsed thoroughly.

This does not only clean the thermos but also removes any lingering odor from inside.



Repurposes your egg shells by drying them out in the sun and crushing them.

Put the crushed shells inside the thermos with hot water and shake. The shells will help break up any of the residue and stains that are in the thermos.



Take a thermos with the stains and put a tablespoon of salt in with some ice cubes. The salt acts like a non-toxic abrasive. Now close the thermos and gently shake. Pour the ice out and rinse thoroughly. This will completely clean the bottom surface of any stains that were inside.


Distilled white vinegar

This is one of the best ways to safely clean out a thermos of any stains. To begin, make sure the thermos is completely dry on the inside. Pour about 4 tablespoons of the distilled vinegar, (you may substitute white vinegar with apple cider vinegar), into the thermos and vigorously shake it for five minutes. Let the thermos stand for 10minutes after shaking to allow the remaining residue to loosen. Pour the vinegar out and then rinse out with plain water.


Lemon juice

Pour about 15ml of lemon juice in and then shake it briskly for about 30-60 seconds. When finished, make sure you rinse it out well. You will not want to leave any Lemon juice behind any as it can ruin the taste of the hot beverage you put in it. Once you have rinsed properly, turn the flask upside down with the opening facing the dish rack and leave.


Dishwasher powder

When trying to remove coffee stains or other stains from a thermos, put one tablespoon of powdered soap that is used for a dishwashing machine into the thermos. Pour hot water in and leave for +-10hrs with the lid off.  The next morning rinse thoroughly with water and use.


These are some of the best, safest ways to remove the coffee or tea stains from your thermos. All the above are general household items that are readily available. This will allow for everyone to use and clean them effectively. Feel free to use them all to see which one is suitable for you.