The dirt that accumulates between the joints, almost always a mixture of dust, residues and mold, darkens them until they completely lose their original color. The result is a floor that, although new, immediately looks old.
Conventional cleaning products, the ones we normally buy to wash the floor, are certainly not suitable for cleaning grout lines.
Here is the most effective trick to lighten black grout and clean the floor.
All you need is baking soda, a sponge, and some water.
Pour some baking soda into a bowl, add some water, and pour it on the floor. Rub with the sponge, making a little force between the joints, then mop as you usually do.
It is not necessary to use a cleaning product. Conversely, using a little vinegar as an alternative to floor detergent will help disinfect surfaces and scent the house.
You will see that with this simple trick the floor joints will be as good as new again.