Bleach the Grout

Dilute chlorine bleach (1 part bleach to 10 parts water), apply to grout lines with a spray bottle or sponge, let it sit for 5-10 minutes, scrub with a stiff brush, and rinse thoroughly. This is effective for stubborn mold, mildew, and deep discoloration on white or light-colored cement grout only.

Why It Works

Sodium hypochlorite in chlorine bleach is a powerful oxidizer that breaks down mold, mildew, and organic stain compounds at the molecular level. It also disinfects, killing bacteria and mold spores embedded in porous grout that scrubbing alone cannot reach.

Tips

• Never mix bleach with vinegar, ammonia, or other cleaners -- mixing bleach with acids produces toxic chlorine gas, and mixing with ammonia produces toxic chloramine gas
• Work in a well-ventilated area and wear gloves and eye protection
• Avoid using on colored or dark grout -- bleach will lighten or discolor it
• Do not use on natural stone tiles (marble, travertine) as bleach can damage the surface
• Rinse the area thoroughly after cleaning to remove all bleach residue