It is a little harder to clean because the hole is too small for you to put you hand down it but if your throw some diluted lukewarm bleach water in it, and/or some dish detergent it comes clean. I love these bottles. Gives me my daily goal, I do t have to worry about going to get another water bottle or not drinking enough during the day. It’s funny too because I work at a doctor’s office and a lot of my patients say “where did you get that? I need a bottle like that!” Just because it makes you drink water because putting soda in it would take entirely too much time and effort. And it gives you time stamps of where you should be. Plus the rule of thumb is you want to drink approximately half of your body weight in ounces of water. I weight 200 lbs so I should drink about 100 oz of water. This bottle holds approximately 120 oz so it makes a good standardized water goal for the average person. Even if you are smaller because generally if you’re smaller you’re more than likely athletic which is even more of a reason to make sure you get your water in. Great product!