Brass doorknobs may look old, tarnished, and dirty, but the material was never just decorative. Because brass contains copper, it has a natural antimicrobial effect: bacteria that land on the surface are broken down by copper ions within a few hours. For decades, that made brass useful on the things people touched most — doorknobs, handrails, push plates, and hospital fixtures. Then modern taste shifted toward stainless steel, aluminum, and lacquered finishes: materials that looked cleaner, even if they weren’t doing the same disinfecting fucntion. This is the story of how we replaced invisible, sterilising engineering, with the deceptive appearance of cleanliness. (This video was produced by Fineas Jackson.)