Once caught in the trap, how could a coon escape?

This question refers to Grandpa's trap.... a joke he played on Billy.

It was all looking pretty good to me and I was on the point of saying so, when it hit me. Why, all the coon had to do was open his paw, drop the object, and he was free. It all blew up then and there. I just knew my grandfather was playing a joke on me.

I stepped back and almost cried as I said, “Grandpa, you’re kidding me. That kind of a trap couldn’t catch a coon. Why all he’d have to do is open his paw, drop the piece of tin, and he could pull it from the hole.”