This article explores various forms of archives—such as institutions, collections, records and cities—as urban commons. It highlights the importance of community and institutional collaboration in curating archives to promote learning, discovery and well-being through grassroots initiatives, transforming archives and their urban settings into repositories of collective memories and significant landmarks for their communities. The Pionta complex in Arezzo, a former mental asylum covering approximately 25 hectares and encompassing historical buildings, an urban park and archaeological remains, holds considerable sociocultural, architectural and landscape value. Parts of it are used by the University of Siena and the local health authority (ASL), while the remaining area is a public space owned by the municipality and province, but underutilized because of the stigma of its historical connotations and lack of reclamation interest. This article presents three collective archival practices aimed at regenerating Pionta’s urban life, altering negative perceptions of the heritage site and activating hidden narratives as living urban archives to enhance creativity, social learning, empowerment and community welfare. These practices demonstrate commons-based archive management and informal placemaking, are collaboratively designed and implemented by diverse community members, and provide insights into managing negatively perceived heritage sites.