Spray on let it work and the green coating is gone it will remove all kinds of green surfaces on tiles eternit carports garden houses etc it is easy to use the concentrate just thin it with water max 110 and use the garden pump sprayer or watering can to apply it evenly where required thats all you will not need to repeat the process 1 l concentrate is enough for up to 100m only for outside use caution use roof cleaner safely read labelling and product informatio