If you’re referring to a DIY tip claiming baking soda removes very dark stains, it can help with some surface stains and odors, but it isn’t a universal stain remover.
A safer approach
Mix baking soda with a little water to make a soft paste.
Apply gently to the stained area.
Leave it for a few minutes, then wipe or rinse thoroughly.
Test a hidden area first, especially on wood, painted surfaces, stone, or fabric.
Avoid aggressive scrubbing—baking soda is mildly abrasive and can dull or scratch delicate finishes.
If you tell me what the dark stain is on (clothes, teeth, wood, grout, sink, skin, etc.), I can give you the appropriate method.
