Cleaning a Thermos Flask

by Amy Gordon
(last updated June 18, 2012)


Like bottles, thermos flasks prove to be extremely difficult items to clean. They are often deep and the bottom is very hard to scrub. Maybe one day someone will make a specially designed tool to clean the inside of a thermos, but until that day comes, we have to make do with the tools that we have.

With almost any sort of cleaning task, the most basic items to use are soap and water, so let us start with those. I find the easiest way to clean a thermos flask is to pour hot soapy water into the bottle. Allow the soapy water to soak for a few minutes.

After the thermos has been soaking in water for several minutes, find a small dishcloth and a wooden spoon with a long handle. Wrap the dishcloth around the end of the wooden spoon. Push the cloth end against the inside of the flask, starting with the neck of the thermos. If you twist the spoon in the cloth, it will help make a bigger scrubbing tool. Make sure to rub the entire interior of the bottle. The hardest part is still the bottom of the thermos, but if you rub around enough of the bottom, everything should come right off.

To get the cloth out of the thermos, tip it upside down and coax the cloth out using a combination of shaking the flask and prodding the cloth with the wooden spoon. It should come out fairly easily. Finish off the job by rinsing the now clean thermos flask.

Another idea for cleaning your thermos flask is to fill it with very hot water and add four Polident (denture cleaning) tablets. Let it sit overnight and rinse it out in the morning. A thorough rinsing job should remove the need for scrubbing on the inside.

Do not store the flask with the lid tight between uses. It is best to leave the lid off to help prevent odors from building up, especially if the thermos is at all wet inside. That moist, warm, dark environment is perfect for bacteria growth, which will mean you have to clean the thermos out again before use.

Author Bio

Amy Gordon

Amy Gordon loves keeping things simple, natural, and safe so she can spend more time having fun. Every day she learns new things about making life at home easier and she loves to share it with you! ...


Removing Ink Stains

To remove ink stains from pens or markers, saturate the stain with hairspray. You can also blot the ink away with rubbing ...

Discover More

Removing Teeth Stains

Teeth naturally yellow over time, but products exist to help lessen the effect. Make sure to brush and floss regularly. ...

Discover More

How to Save Seeds from Melons

Melon is a great summer treat. Instead of tossing the seeds from your melons, scoop them onto a paper towel and remove ...

Discover More

Remove Stubborn Stains Quickly Get everything looking clean again: Walls, floors, baseboards, counters, blinds, appliances, and more. Micro-scrubbers easily reach into surface grooves, lifting dirt away. This low-cost 8-pack is great for stubborn stains and touble areas. Check out Mr. Clean Magic Eraser 8-Pack today!

More Cleaning Tips

Spring Cleaning Made Easy

Spring is a great time for renewal, and renewing your home should be no exception. Spring cleaning is an intense ...

Discover More

Removing Residue from Adhesive Tape

It's so frustrating when you remove adhesive tape and it leaves gunk behind, and sometimes that gunk seems impossible to ...

Discover More

Cleaning a Whiteboard

If your whiteboard is now a grayboard, this article is for you. It describes how to routinely dry-clean your board with a ...

Discover More

FREE SERVICE: Get tips like this every week in Cleaning Tips from Tips.Net. Enter your address and click "Subscribe."

View most recent newsletter.


If you would like to add an image to your comment (not an avatar, but an image to help in making the point of your comment), include the characters [{fig}] in your comment text. You’ll be prompted to upload your image when you submit the comment. Maximum image size is 6Mpixels. Images larger than 600px wide or 1000px tall will be reduced. Up to three images may be included in a comment. All images are subject to review. Commenting privileges may be curtailed if inappropriate images are posted.

What is four less than 8?

2012-06-18 16:04:12


I tend to use 4 rinse system for my thermoses, and I clean them immediately after use.

My 1st rinse is very hot water and some dish detergent. I let it soak with the lid on about 10 minutes. Then I pour some out, and shake vigorously, with the cap on tight. I then rinse well.

My 2nd rinse is a mild hot water and bleach solution, which I again leave in about 10 minutes, this bleaches and disinfects everything. I then pour some out, again shake vigorously with the cap on tight, and then rinse.

My 3rd rinse is some vinegar and hot water. I do like the first 2 rinses.,

My 4th rinse is a little bit of baking soda and warm water. And again, I do like the first 3 rinses.

After that, I rinse once with plain water, and place it inverted on a rack to drain and dry out.

Newest Tips

FREE SERVICE: Get tips like this every week in Cleaning Tips from Tips.Net. Enter your address and click "Subscribe."

(Your e-mail address is not shared with anyone, ever.)

View the most recent newsletter.