POR 15, any expierenced users?

The POR 15 comes with a cleaner and a metal prep to use before applying the paint..I have a lot of the metal prep and wondering if it would be good to use on the other parts that im just using spray paint on to help it stick also, or is it specifically for the POR 15 paint only?
I had that also. Its just a cleaner. If you can when you use it rinse it well , its a metal itcher.