The dramatic growth in customer connectivity and the Internet of Things has increased the demand for rare metals, but the extraction, refining and production of these materials can be environmentally damaging. Customers and consumers, meanwhile, are increasingly concerned about sustainability and want their voices to be heard. How and by what means, can B2B companies in the IoT and nanotechnology sector, using rare metals, engage downstream actors to address sustainable challenges in the supply chain? To answer this question, we first define the terms related to rare metals and their challenges; we then review the different methods of customer and consumer engagement proposed in the literature. Secondly, through interviews with companies in the Internet of Things sector and with consumers we analyze the downstream actors' engagement in the context of rare metals through integration methods. The results propose a mapping of the different methods that enable engagement for sustainability objectives.