noimagination

I empty the bladder immediately after use and wash with dish soap, including the drinking tube and valve, even if I've only had water in the bladder. I never store anything in the bladder. If I haven't emptied it during my ride, I do so immediately afterwards To dry, after rinsing I shake all of the water out that I can, loosely stuff some paper towels in the bladder, and dry the drinking tube by whirling it around so that the residual rinse water is forced into the valve, then shake out the water from the valve/blot with paper towel. The tube and valve are the most likely places for mold to develop, they warrant extra attention during the cleaning process.

It's a pain, but I've learned from hard experience (i.e. having to throw away my first Camelback bladder, and a couple of bottles). The combination of sugary drink and any backwash from one's mouth create a perfect environment for bacteria/mold growth. Rinsing/washing/drying bottles and bladders always, and I mean ALWAYS, takes place within half an hour of ride completion - I think of it as part of my "cool-down".