Written by


A Flask or a hip flask is a small container made of metal, typically used to carry a small amount of a favorite spirit while traveling or at events.

When not cleaned regularly, flasks could affect the taste of your drink and potentially pose health risks.

It’s therefore essential to know how to care for your flask to keep it in top shape.

As a mother, it has become a habit to clean stuff regularly will explore the reasons for regular flask cleaning and the methods for cleaning your hip flask.

TLDR; Jump to FAQ section

Why Regular Cleaning of Your Flask is Important

How Does a Dirty Flask Affect the Taste of Your Drink?

A dirty flask could significantly alter the taste of your drink.

The impurities, bacteria, and residue from the previous drinks could settle in the flask and react with new content, causing unwelcome flavors.

Cleaning your flask regularly ensures that your drink maintains its original taste and purity with each pour.

What Are the Risks of Not Cleaning Your Flask Frequently?

Aside from altering the taste of your drink, not cleaning your flask regularly could pose health risks.

A dirty flask could harbor bacteria, germs, and other impurities that could be harmful to you and the next person who uses the flask.

How Often Should You Clean Your Flask?

It’s best to clean your flask after every use. Yes, that’s how frequent it should be.

Failure to clean your flask immediately after use could lead to the build-up of impurities, which could be difficult to remove later.

If you’re traveling and can’t clean it right away, make sure to rinse it out with warm water or some distilled water if available.

Methods for Cleaning a Flask

Method 1: Cleaning Your Flask with Vinegar and Baking Soda

One of the most efficient ways to clean a flask is to use a mixture of baking soda and white vinegar. Begin the process by ensuring the flask is empty and the lid is secure. Next, pour two tablespoons of baking soda into the flask, and then pour a tablespoon of white vinegar.

The mixture will fizz up and clean the inside of the flask. Fill the flask with boiling water and let it sit for about 15 minutes. Rinse the inside thoroughly with warm water and let it dry.

Method 2: Cleaning Your Flask with Hot Water and Washing-Up Liquid

Cleaning your flask with hot water and a washing-up liquid is the simplest way to clean the flask. Start by emptying the flask and filling it with warm water and a few drops of washing-up liquid.

Use a bottle brush to clean the inside of the flask thoroughly. Rinse the flask with warm water and let it dry.

Remember not to brush your ceramic mug to keep them safe. Check out are ceramic mugs safe to drink from here.

Method 3: Cleaning Your Flask with Dishwasher

If it’s dishwasher safe, you can clean your flask by putting it in the dishwasher. Ensure the flask is empty, and then place it on the dishwasher’s top rack.

Use a mild detergent and run the dishwasher on a gentle cycle with warm water. Once the cycle is done, remove the flask, and let it air dry.

How to Clean the Inside of Your Flask?

Step-by-Step Guide to Cleaning the Inside of Your Flask

To clean the inside of your flask, follow these simple steps:

  1. Empty the contents of the flask and rinse thoroughly with warm water.
  2. Fill the flask halfway with warm water.
  3. Add a tablespoon of bicarbonate of soda to the water.
  4. Add a little white vinegar to the mixture. The mixture will fizz up
  5. Gently swirl the flask to ensure the mixture reaches all corners of the flask.
  6. Let the mixture sit for 15 minutes.
  7. Use a bottle brush to scrub the inside of the flask gently.
  8. Rinse the flask thoroughly with warm water to remove all the mixture.
  9. Allow the flask to dry completely before storing it.

How to Get Rid of Stains from Your Flask?

To get rid of stains from your flask, use uncooked rice mixed with warm water and washing detergent.

Fill the flask halfway with warm water, add one tablespoon of washing detergent and a tablespoon of uncooked rice.

Secure the lid and shake the flask to loosen and remove stains.

Rinse thoroughly with warm water and leave to dry.

Can You Use Bleach or Other Abrasive Cleaners to Clean Your Flask?

Absolutely not.

Avoid using bleach or other abrasive cleaners on your flask.

These cleaners could cause irreparable damage to the flask, and bleach could be harmful if not rinsed out thoroughly.

How to Clean a Stainless-Steel Flask?

Different Methods for Cleaning a Stainless-Steel Flask

Stainless steel flasks require special attention when cleaning to avoid scratching.

You can clean your stainless-steel flask using a mild detergent, vinegar, or specially formulated metal cleaner.

Dilute the cleaner with warm water and use a soft cloth or sponge to clean the flask gently. Avoid using abrasive materials, and don’t soak the flask in water for too long.

Here’s a short video to demonstrate washing your stainless steel flask in the correct way,

What to Avoid When Cleaning a Stainless-Steel Flask?

Avoid using abrasive materials such as steel wool or harsh chemicals like chlorine bleach.

These materials could scratch or damage the stainless-steel surface or ruin the flask’s insulating properties.

How to Insulate Your Flask After Cleaning?

If you want to keep your drink at the desired temperature after cleaning your flask, preheat or pre-cool the flask before filling it with your favorite beverage.

To preheat or pre-cool your flask, fill it with hot or cold water and let it sit for a few minutes.

Empty the flask and fill it with your preferred drink, and it will stay at the desired temperature for longer. Get into how does a thermos flask maintain its temperature here.

How to Remove Odor from Your Flask?

What Causes Odor in Your Flask?

The most common cause of odor in your flask is the residue of a previous drink or lack of cleaning.

The longer a dirty flask remains uncleaned, the stronger the odor becomes. This is true if you are using a flask for tea, the tea or coffee stain and odor will become harder to get rid of if you do not clean it properly.

Tips for Getting Rid of Odor from Your Flask

To get rid of odor from your flask:

  1. Fill the flask with warm water.
  2. Add a tablespoon of bicarbonate of soda and a few drops of vinegar.
  3. Swirl the mixture around the flask and let it sit overnight.
  4. Rinse the flask thoroughly with warm water, and the odor will disappear.

Can You Use Chlorine or Other Chemicals to Remove Odor from Your Flask?

No. Avoid using chlorine or other harsh chemicals to remove odor from your flask. They could damage the flask and pose health risks if not rinsed out thoroughly.

Now that you know how to clean a flask and keep it in tip-top shape, you can enjoy your favorite beverage while on the go without worrying about residue, germs or impurities.

Clean your flask regularly and follow the tips provided to ensure your flask lasts a lifetime.

But are Hydro flask cleaning different from what I’d just share here?

Learn how to maintain and clean your Hydro flask properly here.



Fill the flask with hot water and a teaspoon of bicarbonate of soda or washing up liquid. Close the flask and shake it well. Empty the flask and rinse it thoroughly with hot water. Use a funnel to pour in your brew of choice.


Before cleaning your hip flask, make sure it’s completely empty. Use a clean towel or cloth to wipe the inside and outside of the flask. If the flask has a narrow opening, try using a tablet designed for cleaning dentures.


It depends on the material of the flask. Stainless steel or glass flasks can usually be cleaned in a dishwasher, but it’s best to check the manufacturer’s instructions first.


Mix one part vinegar and three parts hot water and gently shake it in the flask. Rinse it out thoroughly with hot water and let it dry completely.


Fill the flask with hot water and a few drops of dishwashing liquid. Let the solution sit for at least an hour and then vigorously rinse the flask with hot water.


Let your flask dry completely before using it again. It’s best to let it air dry overnight, but if you’re in a hurry, use a clean towel to carefully dab the inside.