Greyland Acidic Concrete and Masonry Cleaner 5L is a strong hydrochloric acid product for removing mortar and cement, dirt and efflorescence and restoring the appearance from brickwork, concrete and stone. Easy to use and can be diluted to requirements. Can be applied with a brush or sponge. Users should exercise caution and wear suitable protective equipment. Not recommended for indoor use, extreme caution should be exercised if product is used inside - environment should be adequately ventilated and free from sensitive metals.