SOS-50 is a buffered detergent based solution designed for the cleaning of new masonry structures. Similar to NMD 80, SOS-50 can be used on virtually any type of brick, block, stone, cast stone and pre-cast. The main difference is the Hydrochloric Acid has been replaced with Organic Salts, which allows for a more environmentally safe cleaner. There is still no scrubbing required.