The banana would have the right skin resistance to clean an old deck of cards. But the oils that it leaves would probably increase the amount of dirt build-up during use. Not on a decent deck, thank you. And the smell.... Not one of my favorites. Can you imagine performing with banana smelling cards?? I don't think so. What's next, a grapefruit? Yeah, put a nice round grapefruit on a rotating spindle and simply pass it over your dirty cards. The rotating grapefruit will do all of the mechanical cleaning. And with a fresh citrus scent. I think I have something there ! ! ! !