Plain water, warm water mixed with mild dish detergent or organic soap or flour mixed with mild dish detergent are some home remedies for cleaning marble. Plain water or water with dish or organic soap is for everyday cleaning. Flour mixed with dish detergent is for deep stains.
Clean spills immediately. Fill a spray bottle with warm water and add 1 teaspoon of mild dish detergent or organic soap. Spray the marble, and clean it with a soft cloth. Avoid using vinegar, ammonia, lemon and most store-bought cleaners, because they can damage marble.
For deep stains, make a poultice. Mix 1 cup of unbleached flour with 3 tablespoons of mild dish detergent. Use a spatula to spread the mixture over the stained area to a thickness of about 1/2 inch. Cover with plastic wrap and let it sit for 24 to 48 hours.
Wash the poultice with soap and water. Reapply if the stain remains.