RUSTED METALS – OSPHO is a rust-inhibiting coating – NOT A PAINT You do not have to remove tight rust. Merely remove loose paint and rust scale, dirt, oil, grease and other accumulations with a wire brush or pressure washer and let dry – apply a thin coat of OSPHO as it comes pre-diluted in the container.Click to see full answer. Keeping this in consideration, how do I get rid of Ospho?To neutralize the Ospho MUST be wet, so if dry, re-wet with itself and let set one or two minutes and with a clean rag and water, wipe off like washing the car and then dry. Next, then da car with 80 grit, clean with 700-1 wax and grease remover, let set an hour and coat with an epoxy.Similarly, can you use Ospho on stainless steel? The bottom paint can be painted after rinsing with water and drying. Phosphoric Acid and Oxalic Acid are great for cleaning stainless steel. It is used to etch Aluminum before painting and should never be left to dry on aluminum. In this manner, is Ospho any good? It’s a great product and have used it successfully for years. OSPHO is a brand of phosphoric acid manufactured by The Skybryte Company. It converts rust into a zinc phosphate which makes a great pre-primer. It will look powdery white/grey when completely dry.How do you use Ospho rust converter?Before applying, use a wire brush or wire wheel to remove loose paint, rust scales, dirt, oil, and anything else accumulated on the surface. After doing this, apply a coat of Ospho and let it dry (overnight). Once the surface is dry, you can paint over it.