Quote Originally Posted by tulip
I only drink water (no sugary drinks that molds like), and I find that if I rinse them out right away after a ride, and put them in the dishwasher, they are fine.

I think the same would work for water bottles with sugary drinks--just rinse thoroughly as soon as possible, and put them in the dishwasher. If you don't have a dishwasher, getting one of those bottle brushes might work well.

+1, only drink water on the bike, and dishwasher works great. It also has some high heat settings for any nasties that you might find.

I do hand wash the Polar bottles, but usually within a couple hours of riding, and almost always just drink water.