The application of clay to the heads of deceased hunter-gatherers within the Middle Neolithic burials of Finland and Latvia was originally identified by researchers working in these regions during the 20th century. This practice stands apart from the deeper-seated traditions of grave adornment which characterise the hunter-gatherer archaeology of the Baltic region during the Middle Holocene. However, the variable extent to which these ‘death masks’ are preserved and recorded has confounded attempts to discuss their meaning or significance in detail. This paper approaches the problem through a discussion of the materials involved in masking, rather than the forms represented by the masks themselves. Through this discussion, an understanding of the relationship between material ontology and cosmology emerges, which is subsequently situated within a socio-historical context through a review of the available radiocarbon dates and broader patterns of social change in the Middle Neolithic archaeology of the Eastern Baltic.