‘Refining through Digestion’ is an exploration in material design that involves collaborating with organisms capable of converting textile waste into a circular system. The research investigates how a practice-led design approach utilises biomimicry, biomaterial, and bio-collaboration to reduce our textile waste resolve and increase circularity through alternative, biological systems of waste recycling. This endeavour offers solutions for creating new material hybrids and/or facilitating the degradation of fibers. Through experimentation and speculation, I conducted trials cultivating mycelium under various conditions and observed how textile waste feeds (such as polyester, cotton and a polyester wool blend) interacted with this process. These observations aided the refinement of mycelium growing methods. The process yielded a material with potential applications for artistic, architectural and agricultural practices, as well as industrial settings. My focus was on artistic design of an installation that can evoke hope through the resilient, adaptive sensibility of mycelium, as well as a proposition for a new biomaterial. Collaborating with living organisms opens avenues for exploring possibilities beyond mere product outputs. It fosters a deeper consideration of resources and contributes to the development of sustainable outcomes. By reconnecting and recalibrating our relationship with biological systems, we pave the way for applying these insights to future materials and practices.