Combine the laundry detergent, multipurpose cleaner and water in a spray bottle. Shake the bottle vigorously until the powdered detergent has dissolved. Substitute half the water with bleach if mildew is growing on the vinyl railing.
Spray the surface of the vinyl railing with the garden hose. Add a spray nozzle to the hose and blast dirt away to reduce scrubbing time.
Spray the cleaning solution directly onto a soft sponge. Wipe the vinyl railing with the soapy sponge, starting at the top and moving upward. Lay a towel under the section you are cleaning if you want to avoid dripping onto the deck or patio.
Wipe down the cleaned vinyl railing with damp towels. Wait for the surface of the vinyl to dry completely. Rub in the vinyl protectant spray after spraying it on a clean dry towel.