Hard water deposits and limescale can both cause unpleasant white stains on black formica kitchen or bathroom counters. Formica is relatively easy to care for, because it doesn't get scratched or etched easily. Avoid using abrasive cleaning tools or powders as these can mark formica surfaces.
Add a few drops of washing-up liquid to 250 ml (1 cup) of warm water.
Mix until soapsuds form in the water.
Dip a sponge into the mixture and rub it over the white stains on the black formica. This might remove some of the white stains, but may not remove all of them.
Gently scrub the white stains with a soft-bristled brush.
Rinse the area with clear water.
Mix 15 ml (1 tbsp) of distilled white vinegar with 45 ml (3 tbsp) of water. Vinegar will cut through the stains without damaging the formica.
Soak a cloth in the vinegar mixture and wring it out so that it is not dripping wet.
Lay the cloth over the white stains and let it sit for several minutes until the white stains disappear.
Wipe up the stains with the soaked cloth.
Rinse the area with clear water and let it dry completely.