How to remove black from floor joints

When combined with water, it is one of the most effective cleaning products on various types of surfaces.

Pour the water and baking soda into a bowl and mix until creamy.
Use a toothbrush to apply the paste to the joints and let it sit for 5 minutes.
Scrub the toothbrush between the joints to remove dirt, then rinse.
Hydrogen peroxide

A product that is part of the first aid kit, but is also very useful for cleaning, disinfecting and whitening the joints.