Spread plastic sheeting out to cover the carpeted stairs. Run a utility knife along the edge of the carpet to cut off the excess plastic. Leave a half-inch of space between the plastic and the rug's edge.
Apply tape down the edge of the carpet. Make sure that the tape secures the plastic to the rug and also hangs over the edge of the carpet slightly. Smooth the tape down to secure.
Press the edge of the tape under the carpet runner with a butter knife. Press the tape under until it is completely covering the carpet. If you don't have a runner and the carpet sits up against a wall, press the tape to the wall to secure.
Clean each step and rail with de-greasing cleaner. Wipe the area thoroughly to remove dirt and residue. Focus heavily on those parts of the railing that get the most exposure to the oil from hands.
Sand the steps and the railing lightly with medium grit sandpaper. Sanding will provide some tooth and allow the primer to adhere. Wipe away sanding dust with a damp rag.
Apply a coat of primer to the steps and railing. Choose a bonding primer that is good for all surfaces. Brush on a thin coat of primer with a paintbrush and let it dry for two hours. Apply a second coat. Allow the primer to dry for four to six hours.
Paint the railing with a trim brush. Use interior latex paint. Work from the top of the railing downward to avoid visible drip marks. Apply two thin coats of paint.
Roll paint onto the steps with a smooth foam roller. Use deck, porch or floor paint for the steps. A smooth foam roller will give you a smooth, even coat of paint. Apply two to three thin coats of paint, allowing each coat to dry to the touch before applying the next.
Apply a urethane topcoat to the steps and railing. This help to protect the paint from scratches. Apply three coats of topcoat with a clean paintbrush.