Step 1
Sweep all dirt, sand and other debris from the landscaping stones. Spray the stones with a water hose to remove dried mud or other materials.
Step 2
Use a pressure washer to clean the landscape stones, if available. When ready to clean the stones, start the pressure washer and stand away from the area. Use a sweeping motion, as with a broom, close enough to remove mold and fungus, spraying at an angle to prevent debris from being blown back.
Step 3
Spray the areas on the stones with remaining mold or fungus with vinegar from a spray bottle and allow it to penetrate. Use a scrub brush on these areas to remove the mold and fungus. Rinse with water.
Step 4
Use bleach and a scrub brush to remove stubborn mold or fungus from the landscape stones. Use a solution of 1/4 cup bleach to 2 gallons of water and scrub until you no longer see the mold. Rinse with water. A second application may be needed to completely remove the stain.
Step 5
Removing gum or tar from the landscape stones often require the use of special cleaners for flagstone. The detergent will break down the gum or tar for easy removal.