HEAVY DUTY CLEANER is an acid-based, biodegradable, and concentrated, gel-based cleaner intended for the removal of contaminants and severe black carbon staining, dirt, and grime on concrete, natural stone, unpolished granite, brick, and stucco. When using on limestone, marble, or any calcareous stone, limit dwell times to 10-15 minutes. It also removes weathered form release agents and curing compounds on concrete at least six months old. The product is designed for exterior use on buildings, monuments, and concrete structures.