Over time, your deck can become discoloured by dirt and grime and the effects of sun. Cleaning with a pressure washer will prepare the surface for painting or staining. A medium duty pressure washer and deck cleaning solution is what you'll need to do the job.
It's a good idea to wear goggles to protect yourself from splashes. Use a low pressure detergent tip to apply the deck cleaning
Clean railings from the bottom up. Let the solution work for 5 or 10 minutes. Switch to a low pressure tip to wash off the solution. Empty the detergent dispenser, and purge the pressure washer.
Begin rinsing off the solution.
Clean a couple of boards at a time, working with the direction of the grain. To clean the railings, start at the top, and work down. This will prevent the formation of streaks.