For 15 years, the University of Idaho has conducted chemical testing of excavated materials from historical sites throughout North America. The most common artifacts tested are sealed containers. Some come from current excavations, but most are from repository shelves. The immediate purpose of the archaeochemistry work is twofold: to identify the contents of the containers for researchers and to provide training for students in analytical chemistry. After testing more than 500 items, project personnel have recognized some unexpected outcomes that have implications for institutions housing the artifacts. Specifically, tested materials identified the small, yet consistent, presence of certain artifacts that can have health implications for personnel working with the items. The article concludes with general guidance on identifying and assessing those risks.