Instruct: Classify Amazon reviews into positive or negative sentiment
Query: GROWS MILDEW!!!

This cup was great except for the fact that it grows mildew in recessed spots very easily,inside the little mouthpiece we found it FILLED with smelly mildew. Tried to clean it but nothing to do, It was really great at first and I feel so disapointed by the sippy cup...Now I have to trow it away which will create "again" more waste on the earth and get a new one, other brand of course and easier to clean....