This semi-drying fish oil based product helps prevent rust and corrosion on iron and steel. Wattyl Killrust Fishoilene will creep into crevices, and penetrate rust, displacing moisture and air, which are the two main causes of corrosion. It is recommended for the coating of badly rusted (greater than 5% rust spots) roofing iron as a means of prolonging the life of the iron. Fishoilene is an anti-corrosive protective fluid for rusted steel where normal surface preparation is difficult.