How to Clean a Stainless Steel Flask

The tradition of carrying alcohol around dates back to the Middle Ages and remains popular today. However, like any popular gift routine maintenance needs to happen in order to maintain the luxury shine of the original item.

Limit Storage Time

Try not to store liquor in a flask for more than 3 days, otherwise it can start to taste metallic. If you forget to clean your flask right away, there are some things you can do to sterilize it and get rid of any debris in there.

Stainless Steel flasks are designed to be thin and portable. This design is great for people who need to carry one around, but can also make cleaning them a difficult process. The narrow opening makes it pretty much impossible to get a rag or a sponge inside.

Fortunately, you do not necessarily have to use a sponge to clean out your stainless steel flask. There are many ways to clean out your flask without using harsh chemicals:

White Vinegar

White vinegar is easy to come by, perfectly healthy to consume, very acidic and has been used as a cleaning agent for many years.

The best way to use white vinegar is to just pour it into your flask and shake vigorously. Shake it for a little while until you feel like your flask is clean. After you shake your flask, dump the vinegar out and rinse out your flask with water. The smell is probably going to be quite pungent, so be ready for it when you open your flask up!

After you rinse out the flask, leave it open and upside down. This helps drain it out and prevents any water from staying on the bottom of the flask and getting funky. Make sure that there is no water or any liquid inside of your flask before you recap it. It is unsanitary to cap and store a flask that is still moist.

Avoid any vinegar that is not distilled white vinegar. These can leave a taste in the flask and can make your liquors taste funny. If you cannot find white distilled vinegar, then just use water. Never use soap on the inside of your flask as it can leave a residue causing any future drinks taste like soap.


Plain water can be used to clean a stainless steel flask, especially if you do not change the type of liquor you drink often. The best way to clean a flask with plain water is to boil two cups of tap water. Pour this water into the flask carefully and avoid it touching your hands.

Once the water is in the flask, cap it and shake it vigorously. Once you have shaken the flask vigorously for 30-60 seconds,uncap it and dump out the liquid. Rinse your flask out with tap water a few times and then let it air dry.

Lemon Juice

Lemon juice is very acidic and does a good job of cleaning out a dirty flask. If you do not like vinegar, then lemon juice is probably the best way for you to clean out a dirty flask. Either pour the lemon juice in full strength, or dilute it with water. The stronger the lemon juice, the better it will clean.

Shake the lemon juice vigorously, just like you would with vinegar or water. You should probably shake it for about 30-60 seconds until you feel like the inside of the flask is clean. After you shake it, make sure to rinse it out well. You do not want to leave any trace of lemon juice in there because it can ruin the taste of your liquor. To dry the flask, you simply need to leave it open and upside down. Make sure that there is no extra liquid in there before you close it up.

Always remember to thoroughly dry your flask before refilling it with alcohol and regular cleanings will help extend the life of your flask for years to come.