Bests & Worsts Reviews from Amazon

I have been using this cup for the past month, my baby took to it quite fast and liked drinking from it. I used the cup for drinking water only and washed it and changed water everyday. I was quite amused and partly impressed with the mechanism of how it worked. But I should have known that any part with so many holes and crevices will obviously eventually fail - and that fail occurs here in the top silicone cover: regardless of how many times you wash it and how well you wash it, it will grow mold in the small seating hole that seats the plastic ball valve. Today I found black mold in the top silicone cover. inspite of regular cleaning, this will veentually occur because it is constantly in contact with water when in use and also after washing when it is out to dry, because the design and material are such that it forms a really small pocket of water that refuses to let go of the water droplet easily / naturally. Pictures are attached after washing with hot water and soap and vinegar, and finally having to admit it is not grime but mold! Munchkin MUST realize that this is a baby product and they CANNOT afford to make such a design that allows rapid mold growth even under such sanitary methods of use. The idea of this cup was good but the design is totally flawed and unacceptable.