Krud Kutter Rust, Calcium, & Lime Stain Remover eliminates built-up rust stains and mineral deposits. This rust, calcium, and lime stain remover is perfect for tough stains in the bathroom, kitchen, garage, patio and all around the home. Tough on built-up mineral deposits & rust stains. Rust-Oleum Certified. Indoor & outdoor applications. Ideal for showers, bath tubs, showerheads, sinks & more.