Removes and prevents rust in 1 step. Removes hard water, calcium, and lime deposits. Water-based formulation penetrates into every void of a metal surface and dissolves rust and oxidation through chemical action. When dry, Must For Rust accepts any primer, paint, coating, plating, welding, etc. Provides a clean surface free of contaminants. Safe, fast, effective on rusted or new metals, chrome, brick, concrete, stucco, fiberglass, porcelain, ceramic, and glass. Not for use on marble.