If you notice green stains on your brick patio, chances are it is moss. Some people actually like the look of moss on their brick patio and will leave it alone to take its course. However, others want to their brick to return back to its original look. Before you try any of the cleaning methods below, it is essential that you test them in an inconspicuous spot first to test for damage before proceeding to clean the more obvious areas of your brick patio.
Power wash the moss from the brick patio. Spring until fall while the moss is actively growing will yield more favorable results; however, moss can be successfully removed by power washing in the winter if necessary. Use a power washer filled with plain water and with a pressure that is 3,000 or less pounds per square inch (psi). Don't tighten the nozzle too much; you do not want to damage the bricks. If power washing does not rid your brick patio of all the moss, proceed to the next steps.
Remove as much of the moss as you can with a broom or a stiff nylon brush. Sweep or wash the loosened moss away.
Mix one part chlorine bleach with nine parts water in a spray bottle or bucket. Alternatively, use one part white vinegar with one part water. Wear old clothes, rubber gloves and goggles to protect yourself if you decide to use bleach.
Clean the bricks. Soak the mossy area with the bleach or vinegar solution and let it sit for about a half an hour to an hour. Then, scrub the area with a stiff nylon brush. Rinse the moss and cleaning solution away with water. Remember to test in an inconspicuous spot first, but this time, check back in a week to be sure discoloring did not occur before cleaning the rest of the patio.