How to Clean Grout Between Tiles

Grout lines are magnets for dirt, mildew, and stains. Because grout is porous, it absorbs everything — water, soap scum, food splatter, and grime. Over time, those once-white lines turn dingy gray or even black.

The good news is that you don’t need expensive cleaners or harsh chemicals. Two common household items — baking soda and hydrogen peroxide — will restore grout to near-original condition.

What You’ll Need

• Baking soda (about 1 cup)
• Hydrogen peroxide (3% solution — the standard brown bottle)
• Water
• An old toothbrush or stiff-bristle brush
• A spray bottle
• Rubber gloves

Method 1: Baking Soda + Hydrogen Peroxide (Best Overall)

This is the most effective DIY grout cleaner and works on floor, wall, and countertop tiles.

Steps:

1. Sweep or vacuum the area to remove loose dirt and debris.
2. Make a paste: Mix baking soda with a small amount of water until you get a thick, spreadable consistency (like toothpaste).
3. Apply the paste directly to the grout lines. Use your fingers (with gloves) or a small spatula.
4. Let it sit for 10-15 minutes. For very dirty grout, let it sit overnight.
5. Spray hydrogen peroxide directly over the paste. It will fizz — that’s the reaction breaking down stains.
6. Scrub with an old toothbrush or stiff brush, working the paste into the grout.
7. Rinse with clean water and wipe dry with a towel.

Why it works: Baking soda is a mild abrasive that physically lifts dirt, while hydrogen peroxide is a natural bleaching agent that kills mold and lightens stains. Together, they tackle both the cause and the appearance of dirty grout.

Method 2: Vinegar Spray (For Mild Stains)

For lighter grout staining, vinegar alone may be enough.

1. Fill a spray bottle with undiluted white vinegar.
2. Spray directly onto the grout lines.
3. Let it sit for 5-10 minutes.
4. Scrub with a brush and rinse with water.

Warning: Avoid vinegar on natural stone tiles (marble, travertine, limestone). The acid can etch and damage stone surfaces. Use the baking soda method instead.

Method 3: Steam Cleaning (For Deep Grime)

A steam cleaner with a brush attachment is excellent for grout — the heat loosens dirt without any chemicals.

1. Fill and heat your steam cleaner.
2. Use the brush attachment to run along grout lines.
3. Wipe away the loosened dirt with a cloth as you go.
4. This works especially well in the bathroom and kitchen.

Sealing Your Grout

Once your grout is clean, protect it with a sealer:

1. Make sure the grout is completely dry — wait at least 24 hours after cleaning.
2. Apply grout sealer according to the product instructions (usually a brush or spray-on application).
3. Wipe excess sealer off the tile surfaces.
4. Let it cure for 24-48 hours before getting the area wet.
5. Reapply every 1-2 years to maintain protection.

Sealed grout repels water, dirt, and stains — making future cleaning much easier.

Prevention Tips

• Seal grout after installation and reapply every 1-2 years.
• Wipe up spills on tiled surfaces immediately.
• Use a daily shower spray in the bathroom to prevent soap scum buildup.
• Ventilate bathrooms — use the exhaust fan during and after showers to reduce moisture.
• Mop tiled floors weekly to prevent dirt from settling into grout lines.

The Bottom Line

The baking soda and hydrogen peroxide paste is the best DIY solution for dirty grout — it’s cheap, effective, and non-toxic. Once clean, seal the grout to keep it that way and make future cleaning a 2-minute task instead of a 30-minute scrub.

Related Guides

• How to remove hard water stains — mineral deposits contribute to dirty grout in bathrooms.
• 12 surprising uses for baking soda — baking soda is the core ingredient in this cleaning method.