When grout that is unsealed gets dirty, it can be tough to clean the grout due to the porous nature of grout, which allows it to quickly absorb liquids as well as dirt. Here are a few ways you can try to get a stain out of grout on your unsealed stone floor. 

Sweep The Floor

The first thing you need to do is make sure that there is not any other dirt on the ground. It will get in the way of your cleaning and removing the stain. Before you begin addressing the stain, you should either sweep or vacuum your floor and remove any loose debris that is present. Even if you think your floor looks clean, it is always a good idea to sweep or vacuum it because there could be dirt that you don't spot present.

Address The Stain

The next thing you need to do is address the stain. First, you should take baking soda and sprinkle it all over the area where the stain is. It should be applied thickly, so that in the end all you see is a nice layer of baking soda instead of the stain. Once you have applied the baking soda, take some vinegar and pour it on top of the baking soda. It may be easier to use a spray bottle to apply the vinegar; that way you can evenly distribute the vinegar on top of the baking soda.

When the vinegar and baking soda come into contact with one another, they will start fizzing. It will make a popping sound as the baking soda and vinegar react with each other. Let the baking soda and vinegar fizz together for a couple of minutes.

Scrub The Stain

After the baking soda and vinegar have been fizzing for a couple of minutes, take a small brush and scrub the grout where the stain is. A clean toothbrush that is solely used to clean with would work well for this job. Move the toothbrush or small scrub brush around in a circular motion to dislodge the stain.

Rinse The Stain

Next, rinse the area off with some clean warm water. This will remove any remaining baking soda and vinegar and let you see if the stain has been effectively removed. If the stain is still present, you can repeat the process above. It may take a few times for the stain to completely disappear, depending on how deep the stain is and the color of the stain.  

Once you have removed the stain from the grout, you should seal your grout and your stone floor. An unsealed floor will more easily absorb stains and will be tough to maintain over time.