COR-TEN is a type of steel characterized by a high corrosion resistance and mechanical resistance. Exposed to the weather conditions, it forms a stable rust-like appearance coating of dark brown color, which inhibits deeper penetration. For outdoor use, COR-TEN is supplied naturally oxidized, without further treatment. The oxidation will stabilize over a period of 10-16 months. During this period, rust particles may come off, leading to a risk of staining on light and permeable surfaces. For indoor use, COR-TEN is supplied pre-treated with wax. A wax kit is available on request. For cleaning we suggest to proceed with a simple pouncing on the surface without using any detergent or water.