Elaborating on what Jiejie said, if you see that the casino uses a ticket in ticket out system, which is the vast majority of casinos these days, you can stuff all your ratty bills into a machine and then hit cash out without playing a hand, receive a bar coded ticket, and take that ticket to the cashier. There you can explain to the cashier your need for all mint conditioned notes, and since you are such a high roller (your ticket will be much bigger than average) they should accommodate your request.