Your containers were given to me as a gift, and I supplemened the set, to replace my 40-year-okd Tupperware canisters. I like that the containers are square and rectangular making best use of space. However, when using them for powdery substances like flour, baking soda, and corn starch, the lids do not seal. I have lined them with plastic bags, but somehow the powder still gets on the inside of the container, and makes the seal not work, as well as making them unattractive.