Dirty grout makes even clean tiles look grimy. It’s one of those things that ages a bathroom or kitchen faster than almost anything else. And because grout is porous, it absorbs stains over time in a way that regular cleaning just can’t touch.

I used to spend an hour on my knees scrubbing bathroom grout with a toothbrush. The results were okay at best and my back hated me afterward. Then I found a method that actually works with about 20 minutes of active effort. Here it is.

Step by Step:

Step 1: Start with the simplest thing that might work

Before going nuclear on your grout, try a paste of baking soda and water. Mix it to a thick paste, spread it on the grout lines, let it sit for 10 minutes, and scrub with a grout brush (or a stiff toothbrush). This works well on surface grime and light staining. Rinse thoroughly. If your grout looks good after this you’re done.

Step 2: For tougher stains: oxygen bleach solution

Oxygen bleach powder (like OxiClean, not chlorine bleach) mixed with warm water is highly effective on grout. Mix two tablespoons per cup of warm water, pour it over the grout lines, and let it sit for 30 minutes. The oxygen bubbles actively break down the stain without you scrubbing. Then scrub briefly and rinse. This removes most staining that baking soda can’t.

Step 3: For really stubborn black grout: chlorine bleach gel

For mold and mildew that has turned grout black in showers and bathrooms, apply chlorine bleach gel directly to the grout with an old toothbrush or squeeze bottle. Leave it for 10 to 15 minutes open a window and wear gloves. The bleach kills the mold and lightens the staining. Scrub lightly and rinse very thoroughly. This is strong stuff don’t use it on colored grout.

Step 4: Use a grout brush, not a regular brush

A purpose made grout brush has stiff V shaped bristles that fit directly into the grout channel and scrub without wasting effort on the tile surface. They cost about $3 and make the job significantly faster and more effective than a toothbrush. If you’re going to clean grout regularly, this tool is worth having.

Step 5: Seal the grout when it’s clean

This is the step most people skip and then wonder why their grout gets dirty again within weeks. Grout sealer fills the microscopic pores in the grout, making it much harder for stains to penetrate. Apply it with a small brush or applicator bottle along every grout line, let it sit for 10 minutes, then wipe the excess off the tile surface. It takes about 30 minutes for a bathroom and should be redone every year or two.

Quick Tips

A steam cleaner is the most effective non chemical grout cleaning method and is worth renting or buying if you have a lot of tile. The steam penetrates the grout pores and loosens staining that scrubbing alone can’t reach. After steaming, a quick wipe is often all that’s needed.

Always rinse grout very thoroughly after using any cleaning product residue left in grout lines attracts dirt faster and can cause chemical reactions with future cleaning products.

Clean grout transforms how a bathroom or kitchen looks and feels. The key is using the right product for the level of staining and then sealing the grout so it stays cleaner longer. Once you’ve got it looking good and it’s properly sealed, maintaining it becomes much easier a regular wipe down with warm water is often enough between deep cleans.