Use disposable kitchenware and just say something at some point asking people to make sure they toss their garbage so that you don’t have a late night cleaning everything up. That should hopefully address most of the problem and ideally you get a few players who are champs and stay to help cleanup at the end. I think charging a cleanup fee would actually be counter productive because people wouldn’t go out of their way to tidy things up because they figure they’re paying a fee to cover that.