Reading some notes I stumbled along these metallic buff paints and don't understand how they are used. Do you actually rub the paint after it dries or what?

Yes indeed. Using an old tshirt or mototool what ever suits your fancy. just be careful not to remove the paint as you buff.

Does it have to be airbrushed on?

No, but it does work best if it is (more even). You can get some of the paints in rattle can (Testor's Model Master), they work well.

Thanks!

Also, with the buffing metallizer paints, I have found that a verey soft toothbrush works well to 'buff' the painted surface after the paint has dried. It doesn't take the paint down too fast, so it is easily and well controlled. If you can get a baby toothbrush, that works quite well. Also, 'soft' grade tootbrushes. Give3 it a go...

Matt