Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Lids may leak

The idea behind these plastic lids is great, and for many applications will be fine--but be aware that for thin liquids, you may experience some leakage unless you really crank them down tightly. I bought them for an application where the jars contain a very thin liquid (pure ethanol or an ethanol/water mix) and need to be shaken daily. I have to be careful not to shake them too hard, or leave them inverted for even a moment, or they DO leak.