New Clean 60 Patio Cleaner will restore outdoor stone surfaces to a greatly improved condition, regardless of the age and state of the stone. However, hard, encrusted matter such as black lichen will require a bit more effort as it will have become deeply embedded into the stone. If you have a lot of aged, hard lichen or black spots, we recommend that you keep an amount of cleaner back when you apply the solution (see below).
We recommend using a pressure washer when washing away the cleaner for heavily aged / dirty patios. The pressure will lift up the lichen and other stubborn materials that will have been loosened by New Clean 60.
For perfectionists, if you find that some black marks or tough lichen remains: a second, NEAT application using the saved over cleaning solution followed by another pressure wash will really eliminate all traces and give you a ‘good as new’ finish.