Something I have been lax in doing is replacing my cups every year. Well today I got a REMINDER of why you need to do it. I was reheating a batch. It had only been in for 1 minute, not even starting to gel yet, I took it out set it on my bench (wood and clean and dry ) went to grab my knife to break it up and before I could do anything it exploded on me. Thank god it wasnt hot but little shard of glass went everywhere. I will now replace all my cups just to stay safe and I encourage you all to do the same.