The biodeterioration of artistic and architectural heritage represents a serious and recurring problem for museums, local authorities, and private collectors alike, where irreparable damage to unique artifacts can result in immeasurable losses to our shared cultural heritage. Here, we present an overview of the current trends in antimicrobial products used to protect heritage items from microbial colonization and prevent their deterioration. From a conservation-restoration standpoint, we contrast and compare traditional antimicrobial products with the state of the art in antimicrobial nanomaterials applied in the heritage conservation field, highlighting the promising potential of various different nanomaterials, as well as points of concern and clear red flags from some of the emerging research. Through an examination of the growing body of research in the academic literature we offer recommendations and practical advice on selecting appropriate microbiological assays and characterization techniques to better evaluate the in vitro and in situ antimicrobial properties of nanomaterials.