The only sane way to store your kids flat art

A truly unaesthetic rec, but prior to this solution I had a milk crate where all kid art was piled, slowly becoming crinkled messy sedimentary rock. A friend recommended I do what she did, and now I've rec'd this far and wide - get a legal paper sized file box, legal size hanging folders, and label each one by age /grade. We started with "the toddler room" at their daycare. Anything worth saving goes in that year's bin. I still have no solution for the 3D projects, which are everywhere.