I can never get the pieces back in the original envelope. Even after cutting off all the excess from cutting out patterns. I even tried to dry-iron the folds on this one I didn't use. Basically I use a gallon size zipper bag (I like the kind with sliders so I know it's closed). I put the front envelope in front and the instructions with number and pictures facing back, this way I can see at a glance if there's something I want to do again. I press out most of the air so it's flat as possible.
So here's how I store them. So far it works.