Black Ops 6 Zombies' Citadelle des Morts introduces dozens of new Easter Eggs and mysteries, including a strange item called the "Stamp." It sits in your inventory without any indication of what to do with it. If you're confused about what to do with these Stamps, you're in the right place. This guide will explain everything we know about these key items in Black Ops 6 Zombies, how to obtain them, and how to use them.