This paper explores the archaeological evidence for the practice of facial and corporeal dyeing, painting and tattooing in the later Iron Age and early Roman period. The aim is to construct a hypothesis which explains how, why, when and by whom such pigments were worn. Although this hypothesis discusses woad-derived indigo, this is used mainly, although not exclusively, as an experimental tool, as no conclusive archaeological evidence exists which reveals the identity of the 'real' pigment(s). Woad has also long held a place in the popular imagination as the source of the dye which the ancient Britons used to paint themselves. This paper explores the possibility that the cosmetic grinder was the focal artefact used in body painting or tattooing, and was used for grinding and mixing body and face paint. It is suggested that, rather than being a 'Roman'-style tool for cosmetic application from the start, it may have begun life as an artefact first used by the later Iron Age Britons for body painting and expressing indigenous identities.