I've found my camelbak growing mats of black stuff after leaving gatorade in it. No big deal. Rinse it out, fill it with fresh water, then add a capful or two of bleach. Make sure to drain the tube so that the bleach-water mix gets into the tube and mouthpiece and let it sit for a few hours. Then rinse a few times with fresh water, dry and you are good to go. No need to add a perfectly good camelbak to the landfill.