How do I prep this?

I have a polished alluminum hanger for an exhaust on a sport bike. We are just going to paint it black with spray paint. How do I need to prep? Thanks for the help.

Clean the part realy good with dawn dish soap and or a good degreaser to remove any polish residue (silicone) then wet sand it with 320 or 400 grit sand paper then finish off with 600 and it's ready to spray.