This article discusses the value of ethnographic objects in museums and collections, and the challenges of preserving them due to their complex composition and poly-materiality. Specifically, the study focuses on the formation of metal soaps on objects made of metal in contact with leather or wood parts. The study proposes a collaborative approach between conservators and scientists to identify and understand the metal soaps present on a selection of objects from the Ethnographic Museum at the University of Zurich. The authors wish to raise awareness about material alteration in ethnographic collections and museum contexts and to promote communication between different actors in the field, while enabling conservation professionals to confirm the formation of a class of degradation products in the absence of specific analytical techniques.