Miller lite wide mouth aluminum bottles and loose change. Either, bring a cap with you.. buy one before, drink the beer.. keep the cap, or bribe the guy selling beer out of the cart. They can't give you the cap, but you can sweet talk them into looking the other way when they place it down in front of you.
Put some tape in your pocket to cover the lid. As long as it’s all plastic/cardboard and tape it won’t set off the metal detectors! Duct or electrical would work best!