You'll have trouble with the polished part. The surface is so smooth that the powder will have a hard time grabbing hold.

First, you'll need to get all the old wax and polishing compounds out of the metal. Clean in hot water and a good cleaning solution, like Simple Green. Bake it for a little while at about 150-200*F to bring any oils back to the surface. And then clean again. Just like paint, it can't be too clean.

Then you need to roughen the surface a little bit. Use a green scrubbie or 2000 grit sandpaper. If you're going to use a translucent or clear powder, the texture can show through. So be careful about how you apply texture.