The archaeological exploration of Old Kingdom cemeteries provides us with a considerable amount of vessels containing inside traces or, in some cases, even thick layers of white substance, whether mortar, plaster or gypsum, coming from diverse contexts. While these vessels are undoubtedly part of what can be dubbed as repurposed and secondarily reused pottery, they should not be simply overlooked or ignored, as they often provide indirect evidence of rituals or activities closely connected to performing rituals.
Their presence in the burial chambers, shafts and cultic areas can often signify either sealing or purifying rites that were executed during the burial of in the course of later ritual activities.