The short answer
Sweep, then scrub the grout with a stiff nylon brush and a paste of baking soda and water, rinse with clean water and dry. Avoid mixing cleaners, and never use bleach with other products. Acidic cleaners such as vinegar can harm natural stone and some grout, so test first or ask a professional.
On this page
Why does grout turn dark?
Grout is porous. It soaks up cooking oil, mop water, soil tracked in from outside and, in damp rooms, mildew. Over time that darkens the lines even when the tile itself looks clean.
How do you clean grout step by step?
- Sweep or vacuum the floor so grit does not scratch the tile.
- Mix baking soda with a little water into a thick paste.
- Spread the paste along the grout lines and let it sit for about ten minutes.
- Scrub along each line with a stiff nylon brush. Do not use a wire brush.
- Rinse with clean water, wipe up the residue and let the floor dry fully.
What should you avoid?
- Never mix bleach with ammonia or acidic cleaners. The fumes can be dangerous.
- Vinegar and other acids can etch natural stone such as marble, limestone and travertine, and can wear some grout. Test a hidden spot or ask a professional.
- Steel brushes and harsh scouring pads, which can scratch tile and gouge grout.
- Soaking the floor. Standing water can push dirt deeper into the grout.
If grout stays dark after cleaning, is crumbling, or sits between natural stone tiles, ask a professional about tile and grout cleaning or repair.
Want it handled for you? Request a quote and mention what you have already tried.
Related questions
Does sealing grout help?
A sealer can slow staining on some grout, but it is applied after the grout is clean and dry. Follow the sealer's directions and ask a professional about your tile.
Can I use bleach on grout?
Bleach is sometimes used on white grout, but it should never be mixed with other cleaners. Read the label, ventilate well and test a hidden spot. Many people prefer to start with baking soda.
How often should grout be cleaned?
Wipe up spills promptly and scrub grout when it starts to dull, often a few times a year in kitchens and entryways.
Can dark grout be restored?
Light soil often comes out. Grout that is stained deep, cracked or missing may need professional cleaning or repair.
