How to Clean Inside a Stainless Steel Vacuum Flask

Whether you use it for work, camping or on a hunting trip, a stainless steel vacuum flask is invaluable for keeping your drinks either hot or cold.
If you’ve used your flask much, you may have relegated it to the back of the cupboard due to the unsightly stains that seem to be impossible to remove. You’ll be pleased to learn that there’s a solution to a discolored stainless steel vacuum flask, and you probably already have what you need to clean away those stains quickly without heavy scrubbing.

Step 1

Rinse the flask with hot water and empty the flask.

Step 2

Squeeze approximately 2 tbsp. of toilet bowl cleaner into the flask, taking care to turn the flask as you pour so that the cleaner runs down the inner sides and coats the entire surface. Allow to soak for 10 minutes.

Step 3

Fill the flask half full of hot water.

Step 4

Scrub the inside of the stainless steel vacuum flask, using a long-handled bottle brush and brushing lightly with an up-and-down motion to mix the cleaner with the water and remove any remaining stains from the sides.

Step 5

Rinse the flask several times until all cleaner residue is gone and the rinse water runs clear. Your flask will now be clean and ready to use.

Things You Will Need

  • Toilet bowl cleaner
  • Long-handled bottle brush

About the Author

Robin Hewitt began her writing career in 2008. She is the coauthor of several books, including "The Joyous Gift of Grandparenting," which covers the nutritional and fitness needs of both grandchildren and grandparents.