Applying the method is very simple. Sprinkle some baking soda between the joints, then pour in a little vinegar and use a brush (or an old toothbrush, although due to its small size it will lengthen the cleaning time) to scrub well.
Finally, use very hot water to rinse. Make several passes if necessary. The joints should have returned to their initial appearance.
Another effective method for whitening the joints consists in using hydrogen peroxide, which is very effective in fighting mold and humidity accumulated between the joints due to poor ventilation.
Apply hydrogen peroxide directly to the joints and use a cloth to remove any residue.