steve is correct.. i was a spraypainter/panel beater for over 2 years.
with things like this to paint the easiest and best thing to use is scotchie... that stuff ya mum uses to scrub down pots and stuff like that. its better than using paper and much easier.
make sure there are NO shiney parts on them... shiney means it wont stick.
once its all scratched up... prep, prime and paint.