Over the last decades, there have been significant improvements in waste management in contemporary cities - notably technology, methods and policies to improve the collection and recycling of materials. However, the industrial practice of recycling - transforming objects back into material for manufacturing - equates at least in part to cutting short the lifetime of things that may still have value. In addition, it requires significant investment and has environmental impacts that should be factored in. Keeping still usable materials away from waste is therefore of utmost importance. Done the right way, it can also create local opportunities for social inclusion and economic development. This paper summarises some of the findings and reflections of my ongoing PhD research focused not on waste management but rather waste prevention through collective practices of material reuse in cities and regions. It introduces the concept of generous cities as an alternative narrative refocusing the use of technologies and methods to address the excess of discarded materials in a time of global climate emergency and fragmented social bonds. Rather than increasing the speed of collecting discarded material to be sent out to recycling, incineration or landfilling, the research aims at reflecting on the potential value of said material and how to generate social and environmental benefits from it. Generous cities are ones in which material generosity is incentivised and rewarded. Instead of objective efficiency, I intend to highlight the centrality of intentional care - even when performed anonymously - to promote sustainability, regenerate social bonds and enable economic inclusion for local agents. A good proportion of excess materials can generate value - and not only in the economic sense - when they are diverted from the waste stream and handled with skills and knowledge that are usually already present in cities. To ensure that waste prevention is effectively developed within cities and regions, it must be incorporated into public policies. I describe some lessons from my experience with collaborative policy-making in the past. That context informs the path of my research on waste prevention and generous cities. I approach that context using mixed participatory methods, direct observation and co-design. I have identified individual/household behaviour, mapped urban flows of second-hand materials, created and prototyped design concepts, and engaged with an international community of practitioners and researchers experienced with different aspects of material reuse. I am particularly interested in adopting a commons-based perspective - following the work of Elinor Ostrom - to identify and shape the governance of material resources in cities and regions. To achieve that, I have created a toolkit called Reuse Commons, through which local actors can weave systems for material reuse. The current form of the toolkit is described in this paper.