This article discusses the coin-making methods used in Iron Age Britain, specifically those used to manufacture the cast bronze coins of Kent. The distinctive markings that appear on the coins reveal a series of mould-making experiments that optimized the casting process. The spirit of experimentation and innovation is somewhat akin to that of modern day industrial engineering, and shows Celtic metal-working technology at its best. The hypothesis that papyrus was used in the mould-making procedures is refuted by an analysis of the striations that occur in the fields of some of these coins. -- AATA