Instruct: Classify the given Amazon review as either positive or negative.
Query: USE WITH CAUTION

They rip easily after they have been heated, usually near the steam opening. They also melted my tubing and I followed as directed...i only have used it twice on my tubing at 6 weeks. First time because i thought clouding was bad, to find out the steam bags do and its normal. Second because some how milk got in the tubing. My hot water in my sink gets just as hot as the microwave so now i just soak them in hot water until i need them again instead.