What You'll Need
A stainless steel thermos flask can still stain, especially when used for coffee and tea. These coffee stains are difficult to remove without the aid of an acidic or abrasive solution lie vinegar and baking soda, so you'll need a cleaning solution that can remove coffee stains with ease!
- Crushed ice cubes and Salt - for the salt and ice method OR
- Denture tablets - for the denture tablet method OR
- White vinegar and baking soda - for the cleaning solution method
- Bottle brush
- Dish soap OR Dishwasher powder - if using the dishwasher
How to Clean a Thermos Flask: A Step-by-Step Guide
The Ice Way
Step 1: Fill the Thermos with Crushed Ice
Fill the thermos with crushed ice cubes - crushed enough to have wiggle room, but not too crushed that the ice melts almost immediately. Add two tablespoons of rock salt into the coffee thermos. This will scrub away the grime and stains without using chemical cleaners.
Step 2: Shake the Thermos to Clean
Close the lid of the thermos tightly, and give it a vigorous shake. Keep shaking the thermos until you no longer feel a strong resistance from the ice cubes moving around. Check your progress every now and then, and add more ice and salt as needed until you notice all the stains have been removed.
It is also a good idea to shake the thermos in different directions. Swirl the stainless steel thermos to clean the bottom of the bottle, and shake it up and down to clean the bottle walls. Doing this will clean every spot of your coffee thermos without missing an area!
Step 3: Wash, Rinse, and Dry
Dump out the remaining contents of the bottle, and wash your thermos by hand with a bottle brush and dish soap, or place it in your dishwasher to clean. Rinse the bottle to remove the loosened grime, and let the bottle dry completely before placing the lid back on.
Using Denture Tablets
Step 1: Place Denture Tablets and Warm Water in Thermos
Dissolve denture tablets in warm water in your stainless steel thermos, and allow the tablet to bubble. Denture cleaning tablets dissolve grime, making it easier to remove coffee stains without having to scrub the thermos clean. This is a good way to clean a coffee thermos that may easily scratch from scrubbing.
Step 2: Let Thermos Sit
Let the dental tabs solution sit in your thermos overnight - the longer you leave it, the more effective the solution will be in removing stains. The solution may bubble and overflow, so it is best to leave your thermos over a catch basin or sink in case of any drippings.
Step 3: Wash, Rinse, and Dry
The next day, remove the contents of the bottle and wash it either by hand or through your dishwasher. If you notice there are still stains in the bottle, you can use warm water and salt to give it a light scrubbing without scratching the coffee thermos. The warm water should soften the grime, making them easy to remove. Rinse and dry the thermos afterwards.
With Vinegar and Baking Soda
Step 1: Fill the Thermos with Vinegar and Baking Soda Solution
To remove deep-seated stains in your coffee thermos, reach for the baking soda and vinegar solution in your pantry. Fill the thermos with equal parts baking soda and vinegar up to the line where your thermos is most stained. Let the solution bubble, as the chemical reaction will lift stains from the stainless steel interior of your coffee thermos.
Step 2: Let the Thermos Flask Sit
Let the solution sit in your coffee thermos for anywhere between 15 minutes to an hour. This will give the cleaning solution ample time to remove coffee stains, as the white vinegar eats through grime, and the baking soda solution lifts stains from your thermos.
Check your coffee thermos after about half an hour. If the baking soda and white vinegar solution looks murky and brown, then dump out the contents and add a fresh batch of cleaning solution to continue the work. Repeat the process until the stains are visibly gone.
Step 3: Use a Brush to Scrub the Grime Away
Remove the majority of the baking soda and vinegar, but do not rinse the bottle. Take your bottle brush and gently scrub the walls of the coffee thermos clean. You should notice the bottle brush easily scrubs away the stains, revealing the shiny stainless steel interior.
Step 4: Wash, Rinse, and Dry Naturally
Wash the thermos by hand. Rinse off any dish soap residue, and dry the thermos naturally before placing the lid back on. You may opt to clean the thermos in the dishwasher with dishwasher powder, which is a convenient way of cleaning your thermos.
Keeping Your Thermos Stain-free
- Rinse your thermos with hot water once you've finished your coffee or tea drink. This will prevent the beverage from staining the interior of your thermos, and remove the coffee taste from your bottle.
- Clean your bottle after use. Cleaning your bottle with hot water or boiling water will help soften any grime, and remove them during your general wash.
- Let your thermos dry before storing. This will prevent stains from mold and mildew that forms in moist environments.
- Use the baking soda method to deep clean and deodorize your thermos weekly. Doing this will remove any lingering flavors or odors that may be left behind by coffee, tea, lemon juice, and other beverages.
Clean and fresh-tasting coffee requires a clean thermos to hold it. When your home isn't clean, you can't expect your drinkware to be sanitary as well. Luce Home is your leading partner in keeping your home clean and well-maintained. Let's get you drinking a fresh brew everyday - right in the comfort of your clean home!
Want more cleaning tips? Check out the other articles in our blog on cleaning kitchen appliances!