A Cafe Scientifique talk by John Stewart, BioArCh, University of York. Despite eggshell being a very common material at many sites, archaeologists have known next to nothing about how most people in the past used this resource, because until recently we have lacked the scientific tools needed to identify it, but now we can begin to explore what eggshell can tell us about our past. We will discuss new developments in archaeological science, before exploring the latest research in this field including Viking Age sites in York, coastal Iron and Viking Age sites in northern Scotland, and the world-famous site of Pompeii.