Green mossy growth on outdoor lawn furniture occurs mostly in humid climates or in areas with high moisture, such as near ponds and water features. Sometimes the green substance is moss and sometimes it is algae. Either way, the green growth is unattractive and will spread if not removed. Although it can take quite a bit of scrubbing to remove moss from porous materials like wood, removing it from metal surfaces is fairly simple.
Move the metal lawn furniture into an open area so that it is easy to clean it.
Brush the areas of moss with a scrub brush to dislodge it from the metal surface of the furniture. The moss will dislodge fairly easily from the metal, and no excessive scrubbing should be required. Continue until you have scrubbed all of the green moss off of the metal lawn furniture.
Mix an oxygenated bleach powder with water as directed by the product packaging. Stir the solution well with a spoon to dissolve all of the powder.
Sponge the solution onto the entire surface of the metal lawn furniture. The oxygenated bleach will kill any microscopic moss and will prevent new moss from growing.
Allow the mixture to sit on the lawn furniture for approximately 20 minutes. Make sure that the furniture is out of direct sunlight.
Rinse the metal furniture off with a garden hose to remove all traces of the bleach solution.
Dry the surface of the metal lawn furniture using a towel, or place the furniture in direct sunlight to air dry.