Wipe down the cultured marble surface to remove the top layer of dust and dirt. For floors, use a soft bristled broom and dust pan. For countertops and walls, use a soft cloth or rag. Never use abrasives, as marble scratches quite easily.
Mix 1/4 cup of pH neutral dish detergent with 1 gallon of water. When choosing a dish detergent, look for words like "Green" or "Eco" on the label. These products will often advertise a neutral pH balance on the product description, either on the front or back side of the label.
Pour a drop or two of your diluted pH neutral cleaning solution over a hidden section of the marble. If the marble begins to show any signs of staining or lightening, dilute the solution with extra water and try again. You should never have problems when using a pH neutral cleaner, but it doesn't hurt to be on the safe side.
Apply the pH neutral solution to your cultured marble surface. For walls and countertops, use a soft cloth. For floors, use a dust mop. Scrub the entire cultured marble surface using your mop and cloth. Don't pour the solution directly over your marble surface, and don't use your cloth or mop while it drips with excessive moisture. By using only a damp cleaning surface, you can prevent water spotting on the marble.
Dry your cultured marble with a soft towel. If you allow a stone surface such as marble to dry on its own, it may become so covered with streaks and water spots that it looks worse than it did before you began cleaning. Since you used only a damp cloth or mop to clean the marble, manual drying should require minimal effort.