KittyD, comic boards you buy at a store that handles old comic books. They use these board to store the comic books.
Usually, come in 300 or 500 pkgs.
riverandwoods, I put shelves in my closet, put the material on boards (was in totes) and yes in was worth the time.
I had a lot more room and could find my colors of material better. My larger pieces I folded and put on the top shelf. Hope this helps.