Cleaning Your Hydro Flask

(The following is an updated and revised version of the original post)

I recommend that before your use your Hydro Flask that you visit the Hydro Flask website and read what they say about Bottle Care. Here is the link: 

https://www.hydroflask.com/caring-for-your-hydro-flask/

I love my Hydro Flasks, all three of them, the 12 oz Wide Mouth, 18 oz Wide Mouth, and 24 oz Wide Mouth. I use one or another almost daily for coffee or tea. Hydro Flask keeps my morning beveridge of choice hot so long that it might take me an hour or more before I finish drinking it.  Furthermore, I have not always been careful to rinse and clean my Hydro Flasks after I finish drinking the contents. That means that there is some residual staining and odor, especially around the bottom were residual coffee or tea has remained sometimes for hours, even a day or more before I rinsed and cleaned the flask, causing even more discoloration and odor.

I finally attacked the stain and smell problem by following Hydro Flask's instructions to “Use baking soda for cleaning: For those stubborn spots inside your Hydro Flask, mix 2-3 tablespoons of baking soda with a small amount of warm water to form a scrubbing paste. Dip the bristles of your bottle brush in the paste and work paste into affected area on the inside of your flask. Repeat as necessary until stain disappears.”

While following the above directions found on the Hydro Flask website helped rectify most of the odor and stain problem, it did not remove everything from the months and even years of buildup due to neglect. Then I remembered a cleaning solution I had learned from someplace else, the source of which I can no longer recall. I poured about a tablespoon of coarsely ground salt into the bottom of the Hydro Flask and using the baking powder paste and brush I scrubbed away.

Whenever the salt disintegrated I either added more salt or started all over with both salt and baking soda paste. After repeating the process three or four times, also applying a fair amount of elbow grease to the brush, I was finally able to remove 99% of the smell and stain. The inside on my Hydro Flasks now look and smell almost new.