Hopefully, this will be helpful to some of you...In error, I placed the lid on my bowl which contained hot food. The seal quickly locked and I was unable to break the vacuum seal on my Lock and Lock bowl after trying to pry it loose with a butter knife, letting it cool, and running warm water around the rim along the seal. As a last resort prior to throwing it away, I tried placing it in my microwave for a few seconds (approx. 30 sec.) and it worked! The lid came off easily, no tugging involved!! I'm glad I didn't have to throw away my bowl. Other than this, I LOVE these bowls!!