Do you wash your dishes after you eat or drink from them? I hope so. Yes you should clean your bottles, the cleaner you keep them the longer they last. Look for bottles that are top rack dishwasher safe if you can or like others have said a drop of bleach and some warm water should do the trick. Especially important after energy drinks. Aside from the free bottles, pros never reuse their bottles on the road because it doesn't take too long for bacteria to form. Roadies hate being sick so clean your stuff, and wash your bibs...your body will thank you.