I admit, I have problems keeping my water bottle clean. No, I don't put anything in there except water. But I use spring water, not sure if that makes a difference. I imagine it does, because it doesn't have chlorine which prevents mold from growing. Anyway, I've tried cleaning the water bottle with dish detergent (the kind that is "safe" if consumed accidentally) - that lasts an hour or so, then it starts smelling moldy again. Almost as bad as just rinsing with tap water. I've tried ammonia, that seems to work for a few hours. I've tried bleach, and I can't recall exactly how well that worked, maybe it worked for a day, but it seemed extreme... hard to get the bleachy smell out by rinsing I think.
So what can I do to get it clean enough to LAST a few days before it needs another cleaning? Is there some magic potion or method of shaking the potion that I haven't heard about? I know the pros just throw their water bottles at the crowd near the end of every race, but I don't have an expense account for water bottles.