A ready-to-use cleaner for patio cleaning. It is also suitable for all outdoor stone & masonry surfaces. Apply and leave for a minimum of 2 hours, it works also works on algae, lichen and black spots, removing dirt and grime even if the patio hasn’t been cleaned for years! The alkaline-based solution won’t damage or etch the stone surface like other cleaners. Apply neat for great results on heavy grime contamination, or apply 1:1 for less dirty areas – it’s an outstanding value. Stonecare4U's Patio Cleaner contains a chlorine type agent as an active ingredient and will stain fabrics and sensitive materials. Take special care to avoid contact with fabrics & tarmac during application. The fluid might cause slight lightening of some surfaces – always try the product in an inconspicuous area prior to use.