Damp, humid conditions coupled with stagnant outdoor furniture cushions can result in a wet surface layer on the cushions that turns into an unsightly mildew growth. Not only does the mildew look unappealing, it can also give off a musty odor. Fortunately, you can remove the mildew and restore the outdoor cushions to their former condition -- even if the mildew has been a resident for a while.
Sodium Borate Cleaner
Pour 2 cups of hot water into a container. Add 1/2 cup of sodium borate to the water and stir with a spoon to mix.
Put on rubber gloves and dip a sponge into the cleaning solution. Rub the cleaner vigorously into the mildewed areas. Allow the cleaner to soak the stains for three to four hours.
Rinse the cushions thoroughly with a water hose and allow them to air dry in the sunlight before replacing them on the lawn furniture.
Tea Tree Oil Spray
Fill a spray bottle with 2 cups of water and add 2 tsp. of tea tree oil to the water. Replace the lid and shake gently to mix.
Spray the tea tree oil mixture onto the mildewed areas of the outdoor cushions.
Leave the spray on the cushions. In a few days the mildew and its accompanying smell will be gone.