To paint over ANY surface, without sanding, use a product called 'ESP Easy Surface Prep', available at hardware and paint shops. Wipe on, wipe off and paint in 90 minutes. Works well over enamel paint , without having to sand. SAVES HOURS of work. It was recommended by a professional painter.
Pretty much the best website ever: knockoff DIYs of retail decor. (anthropologie, ballard design, crate & barrel, land of nod, pier 1, pottery barn, restoration hardware, urban outfitters, west elm, williams-sonoma and others). Truly some of the neatest ideas ever!!