You can either use regular marble cleaner or try removing the stain using grade 0000 steel wool.
Marble stains cleaner.
The best way to address mold stains is to use a product that is specifically designed for removing mold and mildew stains on marble such as this one.
You can create a marble poultice using 6 hydrogen peroxide and a few drops of ammonia.
Marble stains very quickly especially if a liquid is allowed to sit untouched for a period of time.
Dry the surface around the water stain then rub in a circular pattern over the stain until the stain buffs out of the marble.
In most cases this should be sufficient to remove the water stains however if this does not work then we recommended trying a marble cleaner specifically designed to remove hard water stains and soap scum.
Follow the above directions for removing rust stains from marble to effectively remove organic stains.
Here are some poultice recipes diy solutions that can help tackle them i ve also tucked in a recipe you can use for everyday cleaning.
For most organic food stains the marble institute recommends cleaning with a solution of 12 hydrogen peroxide and a few drops of ammonia.
How to clean cultured marble.
1 x research source clean up orange juice wine and coffee as soon as they are spilled.