What Were the Cardboard Scraps Going to Be Used For?

Now, Old Man Gideon, the man who sold Mike the box, gave him 2 rules: One, he must return every scrap he doesn't use, and two, don't ask for extra cardboard. However, Mike ends up forgetting the rules, which causes him lots of trouble. So, if Mike didn't break the rules, what were the scraps going to be used for?