Seeing the flaw in his original currency, The King, decreed a new standard in trading currency. The Bottle cap! The king offered a buy back of Nigels, all authentic serial numbered Nigel notes can exchanged back to the crown for 10x their face value in bottle caps. The bottle cap offers a much more robust currency with an anti inflation measure built in to it. Since the Third Nuclearistic Tremorandiums, the technology to reproduce more bottle caps has been lost. There is a general increase in circulated caps which are introduced into the system with scavenging but this rate is matched by the population growth and offset by the degradation of some caps during conflicts.

A Cap has 4 important features that make it a legal tender:

1. A generally flat steel disk with curved edges. The curved edge has 21 crimped teeth.
2. A rubber seal insert, often with machined raised lettering representing a batch number.
3. A hard resilient paint coating. Untarnished by flexing and scratching the cap by hand.
4. Clearly marked NWW logo and branding in the cap artwork.

A trader or proprietor is within their rights to refuse any bottle cap they may deem not legal tender. Common reasons inline with their features are as follows:

1. Folded over, split, or incomplete caps. Caps that are not metal or caps that no longer have a clear 21 tooth crown to remind us of the Great King Nigel.
2. Missing, hard, or incomplete rubber seals. Merchants are often seen pressing their thumbs into the seal of caps in idle times.
3. Overly tarnished, paint chipped, or bare metal caps.
4. Everyone has heard the excuse "My Caps were in a fire , I cleaned them up, they are only missing paint and seal". If you accept inferior or fake caps, you may not be able to convert them to beer or even trade them on. Be Vigilant and all hail King Nigel.