You might want to play with an alternative closure fastening, to save using the paper clip. And that is to use slot and tab joints at top and bottom.
Cut a slot in the top of one end, and a mating tab at the top of the other end, and reverse the slot and tab cutting at the base.
Fold the upper tab out, and the lower tab in (fold them over a double-thickness piece of scrap), and then slide the two slots into the mating tabs to make the joint. You never need to unfold or re-fold the tabs again. The natural spring of the foil holds the joint closed.
A somewhat blurry photo of the idea can be found here (although the tab folding is in the wrong direction, so the upper tab is in the heat):