Evolution of Caps

Since the whole apocalypse thing, money is now bottlecaps sourced from mostly Nuka-Cola products. It’s clever but a bit clunky, so the Delta started a trend of puncturing holes through caps to conveniently string them together.
It became a little too common and nowadays the scarcer unblemished caps are worth more. Rarest yet is the Nuka-Cola “Gumbo” cap from a failed pre-war promotional product named after the Nola Saints mascot. These highly valuable caps are notoriously impossible to counterfeit due to a strip under the lid that preserves the drink’s flavor. You can tell if a Gumbo cap is real if it tastes like 100+ year old shrimp.