I always save the thick rubber bands that come on broccoli or produce. 
Those things last a long time & don't seem to mind the heat or weather. 
I keep two on my boxes & an extra stash in a utility draw. They fit perfect 
& can be twisted twice around the box at either end. Wrap 'em just once 
& it makes a good gobble. 
Wrapped twice & you can't make the box make noises. Gives me an excuse 
to buy more produce too!