Instruct: Classify a review as either positive or negative.
Query: Won't maintain vacuum over an hour or so

I had high hopes for these containers. Of course, there are plenty of things you can do with them if they work. I initially noticed a problem whan I would come back to the container and the lid removed too easily - no vacuum. I did the (marshmallow) test and, sure enough, the container would attain the vacuum initially but, after an hour or so, it would lose the vacuum. Even though they were new, I did all of the tips and tricks posted on the Tilia web site (cleaning around the rim, making sure there were no crumbs, etc.) Nothing works. Really disappointed. I love the foodsaver and really wanted to utilize the canisters. They just don't work.