Wilko path and patio cleaner concentrate 5 litre is a non acid based exterior hard surface cleaner which can be used on a wide range of hard surfaces such as brick tarmac asphalt block paving concrete and stone unlike acid based treatments this formula uses chemicals to clean instead of corroding away the surface therefore youll get different results compared to our previous wilko hydrochloric acid based formulation the concentrate is specially formulated to remove a wide range of stai