Zep 32 oz. Commercial Grout Cleaner & Whitener is a low-odor, ready-to-use formula that makes cleaning and whitening floor grout lines a breeze. It effectively removes dirt, grime, and even tough rust stains from concrete without the need for harsh scrubbing. This OSHA-approved product is safe for use on floors with colored grout, thanks to its bleach-free, professional-strength formula.