There’s a lot to love about an old-fashioned cast-iron tub. But if you don’t love what the years have done to your antique soaker’s exterior—or just want to introduce a vibrant color to your bath—paint it. While reglazing the interior’s porcelain is a project best left to the pros, you can easily refinish the outside of your tub in less than a day. First, scrub the surface with a stiff wire brush, removing any flaking paint. Then, using a natural-bristle brush or 4-inch foam roller, apply an oil-based primer formulated for metal. Let dry 6 to 8 hours, and brush on a bright, oil-based enamel or epoxy. (Avoid latex paint, as it can cause your tub to rust.) If a second coat is needed, wait 24 hours before applying. Then get set to soak in your bathing beauty.