This was the first thing that came to mind. Also the fact that it's 200 years since the war, and you're only treading where other scavengers and squatters have passed and camped. People collected them for urban legend reasons (get a garbage bag full of bottle caps and we can get this mythical kid a new set of kidneys!), for recycling or scrap, or just littered them around. "Realism" isn't really part of the argument against examining this. Realism in how people behave and logic behind their actions is not an inconsistent thing to look and strive for, even if we aren't always given it. http://fallout.wikia.com/wiki/Bottle_cap I buy this explanation for why they became currency. They resources to duplicate them is nonexistant, there's plenty of them, and they're readily transportable. It also would make a way to duplicate them extremely lucrative and destructive. Great quest hook. This is also one of the best ideas I've ever read: http://3.bp.blogspot.com/_EDQ6oIZ43x8/SkOxdgjDHPI/AAAAAAAAAMs/j3p_ZkR6XBg/s400/so_much_win.png Take out the part about Nuka-Cola starting the war and poisoning the population which doesn't really make sense (the resource wars affected and involved the whole world- for Nuka-Cola to be able to manipulate those events, they would have had sufficient power to establish a one world government from the beginning). The rest is sheer cheeky brilliance. It's something Black Isle would put into Van Buren as a subplot. I see them as a sort of BoS organization, most of their energy devoted to just fighting against entropy (much like the BoS) and maintaining their own little world, while subtly affecting much of the wasteland. Not so heavy on the military force projection. Even without direct access to most locations, they could still be connected thanks to the caps economy, and also have a ready-made way to establish hideouts and spies in new areas. Just send their guys out with some caps after running them through a laundry drier to beat them up a bit like counterfeiters do with money.