This thesis explores the transformative potential of reshaping the way cities handle excess materials. In particular, it explores a shift from industry-oriented waste management to community-based waste prevention through practices of reuse at a local level. The central research question addressed is: ‘How can practices of reuse contribute to reimagining and reshaping the way cities handle excess materials?’. Through a series of interconnected research cycles, this investigation dives into the nuances of cultures of reuse through repair, upcycling and recirculation, and challenges the prevalent mindset focused almost exclusively on recycling, incineration, and landfilling of materials. The research begins by employing design research methods to understand how discarded and unused materials are transformed and re-distributed in urban contexts. It then investigates forms of embodied knowledge in reuse initiatives, in order to leverage such practices with open-source ways of organising community initiatives. Finally, the thesis connects to policy-making, introducing the concept of ‘generous cities’. During the doctoral investigation, eight design concepts were created, and three prototypes developed. Altogether, they capture the research findings and expand their potential impact in establishing local systems of material reuse. The generous city highlights the ability to weave convivial forms of addressing the multiple contemporary crises – social, environmental, economic – by foregrounding collective forms of mutual care, cultural regeneration, and resource conservation. The thesis contributes to scholarship on waste management and urban sustainability, adopting a critical, transdisciplinary, and situated perspective. Additionally, the research offers practical tools to promote and scale community-based waste prevention. It presents an essential pivot from the current focus on recycling towards more sustainable, community-oriented, and generous urban environments.