This open access book covers novel techniques and materials for removing inclusions in metallic melts, resulting in significant improvements to the purity, quality, and materials properties of the cast metal product. It looks at an entirely new generation of intelligent filter materials and filter systems with functionalized surfaces for removing solid and liquid inclusions such as deoxidation products, sulfides, and nitrides carbide from metallic melts. This collection of contributed chapters addresses the overarching goal of the production of lightweight structures and high-demand construction materials within an overall substantially cleaner and more sustainable global supply chain. The chapters cover a diverse array of topics ranging in scope from the development of ceramic foam filters, to in-situ x-ray and optical characterization techniques, as well as advanced modelling of 3D-printed filter structures. Additionally, the book features a number of contributions directly transferable to industrial applications related to the clean metal casting technologies of aluminium and steel alloys.