How to Clean a Flask

A question rarely posed to flask users is how to clean them out. “Drink it” seems to be the consensus, but what to do after the enjoyment seems to be of much debate. Cleaning your flask isn’t a difficult undertaking, regardless of which technique you choose. And no, buying more to drink isn’t an option.


If soap and water isn’t getting the smell and taste out of the flask, pour two teaspoons of white vinegar into it followed by hot water. Shake the flask with the two substances in it to ensure its complete cleanliness, then rinse with hot water. The smell of your last drink will be neutralized, and the taste left from the vinegar will cure the urge to drink.

Baking Soda

The same concept as vinegar, using baking soda will achieve the same effect. Two teaspoons will suffice; pour it into the opening with hot water, close the flask, and shake it up. Make sure you rinse well, or your next drink won’t have as much of a kick to it.


To achieve a more thorough cleaning, a toothbrush or baby bottle brush can be used. Depending on the width of the opening, either tool can help you scrub away the scent. Shake some baking soda on the tip of the brush and run hot water over the opening while you scrub to leave as little evidence as possible. For any of the methods using water, don’t attempt to towel dry; flip the flask upside down in the sink with the top open to let it drain before using it again.

Stainless Steel Cleaner

Not recommended for internal cleaning (for obvious reasons), stainless steel cleaner will give your flask a “just like new” shine. The cleaner can be purchased at any store that carries cleaning products, and can be used for other household products. Using a soft cloth that you’re not too attached to, dab some of the cleaner onto the cloth and rub it on the flask in a circular motion until it shines the way you want it to.

If none of these techniques work for your flask, only two recommendations remain- use a glass or shot glass next time, or get weaker spirits. 100% proof doesn’t prove anything but difficult if you expect a clean flask. No matter what method you use to clean your flask, it would be better utilized if full. Better enjoyed as well, surely.

Betsy Cline

Betsy Cline has been a professional house cleaner for 15 years and also a mother of 4 amazing kids (who make lots of messes). She is the founder of How to Clean It and loves to share tips and advice for cleaning up anything life throws at you.

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