I also use the ziplock bags. I use all the sizes and my favorite is the 2.5 gallon. I use them to hold all the smaller bags for a project so I can just grab and go. Pattern books fit well inside the big bags too. So everything is together. I also use them for completed blocks with a thin piece of cardboard to keep them from getting wrinkled. I cover the cardboard with contact paper. I do have to keep a secret stash of bags hidden in my sewing room so they don't get used in the kitchen by DH.
