Fertan is a water-based rust converter that penetrates and chemically converts rust, leaving a bronzed metal surface ready for washing and painting. It can be used as a protective coating on lightly rusted metal, stubborn rust, and rust-free steel, especially on overlapping panels, seams, welds, and joints of dry or damp metal, without damaging other materials. The 3-step Fertan process involves cleaning, treating with Fertan, and further treatment.