Very white joints in one pass:

Baking soda is the perfect solution for eco-friendly cleaning enthusiasts. It has antiseptic properties that are ideal for removing residue and bacteria from any surface.

Mix warm water with baking soda until you get a creamy consistency. Use an old toothbrush to scrub between the grout lines. After about 20 minutes, wipe it off with a clean cloth or mop, as you normally would.