HG patio cleaner is a highly concentrated cleaner that has been specially designed for the cleaning of dirty and stained concrete, paving slabs and gravel. Pour water over the patio first, paying special attention to the grout. Brush away any puddles. Pour the contents of the bottle and 4 litres of water in to a container which a scrubbing-brush will fit into. A washing up bowl is ideal. Dip the scrubbing-brush into the container and apply the liquid, scrubbing as you go. Now allow a few minutes for the product to work. Then scrub a little while longer and before the liquid dries, rinse the surface thoroughly with water.