The old caustic hot tank solutions need to have the rust remover additive in them to take the rust off. If you use to much of it in the tank you end up with a coating on the part that looks grey instead of how clean cast iron does I agree with John Kunkel on that part that looks like it has been cooked and iron bead blasted


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)