The Osmo Gard Clean is a highly effective green growth remover that will also slow new growth. It is recommended for wood, stone, concrete, bricks, glass and garden furniture.
No scrubbing is necessary, simply pour the liquid directly onto the infested dry surface. Depending on the level of growth or soiling, use either pure gard clean or diluted 1:10 (max) parts water. Apply a thin layer evenly over the affected area and it should be gone within 24 hours.
Gard Clean Product Information
Gard Clean Product Safety Information