How often you use the exfoliating wash really depends on your skin.
Generally if your skin is normal (as in not very greasy and not very dry) then gently exfoliate once a day, preferable in the evenings before bed with the Clarol Silver & Birch Exfoliating Wash before applying the other Clarol products overnight.
However if your skin is very greasy you can increase exfoliation to twice a day, morning and evening, which can improve the greasiness.
If your skin is quite dry then reduce exfoliating to once every other day.
Often when the Clarol products begin to take effect and skin starts to improve, dryness can often result as part of the healing process. In this case reduce exfoliation to every other day.
When exfoliating, always be gentle on skin, don't scrub it too hard and exfoliate using gentle circular movements over the whole facial area.