Tupperware not air-tight or liquid-tight? I received an e-mail from tupperwares that their some of their products...
I received an e-mail from tupperwares that their some of their products are not meant for air-tight or liquid-tight like the square-A-way or square round containers.
Why aren't they tight-proof?
Answers: It would be due to the method the plastic is made during the molding process. If you'll look at the rim & lids you'll see the edges are almost straight where the river tight container has a rounded edge that the lid stamp goes into a channel on the bowl.
The 'burp lids' are the just ones with the tight seals; they DO work.