Rinse with tap water or vinegar diluted with water.
Baking powder and vinegar

Other Remedies for Mold Stains
Like vinegar and baking soda, there are other very effective methods for removing mold stains.

– Hydrogen peroxide to treat mold

In a spray bottle, add a 3% concentration of hydrogen peroxide, then spray the areas to be treated and let it sit for ten minutes. Then scrub with a brush to remove the mold stains, then wipe with a damp cloth. If the mold stains do not disappear, repeat the process.

This antibacterial, antiviral, and antifungal solution, found in most medicine cabinets, can effectively treat mold. In fact, hydrogen peroxide can be safely applied to a variety of surfaces, including kitchen countertops, bathrooms, and bathtubs.