The AI 770 cleaner is recommended for removing salt efflorescence from clinker brick and tiles, porcelain, glazed and terracotta tiles as well as cobblestone. Please note, however, that the cleaner works well in case of deposit. If the tarnish coat is too thick, the cleaner will not clean it completely. If this is the case, first try to mechanically remove the salt efflorescence , using a hard plastic brush. In some cases, the product may have to be used more than once.