as above a scotchbrite pad is good for light rust, a wire wheel (bench or drill mounted) a scraper for loose flakes, fine emery cloth for tricky nooks and crannies. Jenolite rust remover...for finishing Plastikote BBQ Paint available from Wilkinsons stores and B&Q
Theses are are methods I would use but most importantly...keep it clean and clean off the crud regularly after wet riding conditions and remove and paint again when it starts to show signs of rust...dont ignore it exhausts are expensive!