The Celtic craftsmen who worked in Britain in the years before and immediately after the Roman conquest in 43 A.D. were both highly skilled and considerable artists. Their repertory included a number of plating and surface treatment techniques, which have been studied both metallographically and by microanalysis. The examples given here show the coating of both bronze and brass with tin, of iron with bronze, and of copper with a copper-silver alloy. An illustration is also given of how several effects may be combined in one object.