Anyone use 1...perhaps something like this...

https://www.google.com/amp/s/sports.yahoo.com/amphtml/best-hydration-packs-144617091.html

1 thing that comes to mind is how does 1 clean it?

Depending on model and opening most can be hand washed or even turned inside out and run through the dishwasher. I've seen brushes made for the tubes.

I've used a few different hydration packs. Personally, I buy my backpacks with a hydration bladder pocket so I can just insert and go. My problem with the hydration packs is there is hardly enough room for anything. I like to carry extra gear to be prepared for anything. One thing I have learned to love is the bladder with the insulated hose, it keeps the water from freezing or getting too hot.