How to Remove a Stain from Grout on an Unsealed, Natural Stone Floor

Once unsealed grout gets dirty, and it will, there is no easy solution to remove the stain. Because grout is extremely porous, it will quickly take on the mess from dirt, debris, and spills, and it’s slow to relinquish the stain. In fact, the only way to completely remove some stains will be to start over with new grout. But before you take on the expense of replacing the grout, try one of these potential fixes. Remember, it is especially important to spot test when you’re working with unsealed floor surfaces.

• Baking soda
• White vinegar
• A bowl
• Small brush (a toothbrush works well)
• Water
• Bleach
• Rubber gloves
• Eye protection
• Dry towel

1. Before you begin, make sure the floor is dry and free of dust, dirt and other loose debris.
2. Test all cleaning products on a small, hidden area to ensure there are no adverse effects.
3. Pour some baking soda in a bowl (as much as needed to cover the stain).
4. Pour a small amount of vinegar in the bowl (not much is needed, about 1/3 of the amount of baking soda).
5. The mixture will start fizzing as soon as the vinegar touches the baking soda. Quickly stir the mixture.
6. Quickly spread the fizzing mixture over the stain. The fizzing is what will work on the stain for you. Be sure you spread the mixture (paste) over the stain and not just the liquid.
7. Allow the fizzing to continue for several minutes.
8. Scrub the area with a small brush (toothbrush) to work it further into the porous grout.
9. Rinse the entire area with clean water.
10. Once you’ve removed as much of the stain as you can with the baking soda and vinegar, bleach can be used to remove any remaining stains. Wear eye protection and rubber gloves before you begin.
11. Pour a small amount of bleach directly onto the grout. Again, make sure you spot test first!
12. Wait a few moments before scrubbing with the brush.
13. Rinse completely with clean water.
14. Dry with a soft cloth, and allow the area to air dry completely.

• If the stain remains, try a floor steam cleaner. If a home or rental version of the machine doesn’t do the trick, call in a professional to remove the stains.
• If at all possible, seal the grout once you’ve cleaned it. It’s much easier to seal it than it is to scrub every stain, and odds are great that there will be many.
• An alternate way to perform the above steps is to sprinkle baking soda directly on the stain, then pour on a little vinegar. If you want to try that, add extra baking soda around the area to be sure you don’t let any vinegar touch the stone without the baking soda there to neutralize it. Vinegar is very acidic and can etch some types of stone, particularly marble.
• Do not use a different type of vinegar than white vinegar. Other kinds like apple cider vinegar or wine vinegar can stain the grout or stone.