A similar product in Korea killed quite a lot of people a few years ago.
https://www.telegraph.co.uk/news/2020/07/28/14000-people-may...
https://www.telegraph.co.uk/news/2020/07/28/14000-people-may...
It's really amazing to me that "how do you clean this fucking thing?" is such a nebulous concept for the engineers of these devices.
I add a small amount of bleach every other time I fill the tank (a few drops - if you can smell it you've added too much) and once a week I empty it out entirely, wipe it down, and let it dry completely. And, of course, if I'm turning it off for longer than 12 hours or so, I empty it out.
Suboxone maker Reckitt Benckiser to pay $1.4 billion in largest opioid settlement in US history
https://abcnews.go.com/Business/suboxone-maker-reckitt-benck...
Another product they sell: https://www.reckitt.com/brands/air-wick/