Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Unsanitary nipples

My son could drink out of it fine, but it won't seem to clean properly after using pediasure strawberry flavor. It just sucks up the smell and who knows what else I bought the glass bottle yesterday, put the pediasure in it an hour ago, he drank it, I washed it, boiled it washed it again, and I simply cannot get the aroma out of this very very soft nipple.