Ok, sounds like a very rational process. I'll bet Merlin taught you that! (now if I could only find my wizard's hat).:)

Muriatic Acid
 

Muriatic is NO JOKE! I used to work in a hard-chrome plating shop many years ago and we used the stuff to clean cast steel and iron before plating.

Depending on the concentration, this stuff will begin to "etch" the surface of your metal very shortly after contact.
Be careful and good luck with your project.....................RayT