The storage containers aren't the real problemit's the lids. Lids get separated from
their containers and flop all over the place. This solution keeps lids contained and stored
beneath their owners!
Two cardboard inserts give both stiffness for ease-of-use and a flat surface so containers can be stacked
on top of lids. Cardboard can be removed and covers washed.
If your lids don't naturally fit into a square container, then use
the instructions for rectangular lid holders