Monnaie d’échange transforms two ordinary by-products of the food industry, coffee grounds and discarded milk, into a contemporary form of galalith. Using these low-value materials, sourced from cafés, dairies, and everyday French consumption habits, the project develops a local, dense, sculptable, and repairable material designed for personal care objects. The coin becomes a symbol of this transformation: what once had no value is given a new form, purpose, and circulation. The project thus questions the way we produce, discard, and redefine the value of materials. Bridging craftsmanship, experimentation, and industrial production, Monnaie d’échange seeks to approach waste not as an end point, but as the starting point for a new exchange between territory, body, and production.