To keep granite countertops clean, Once a week wipe down with a damp cloth and a stone cleaner formulated with a neutral pH. Never use harsh chemicals or abrasive cleaners. They can scratch, pit, and etch the surface of the stone. For oily stains, try a poultice made of a cup of flour or baking soda and 5 tablespoons of dish soap. Add water to make it the consistency of sour cream or yogurt. Place the solution directly on the stain and cover with plastic wrap overnight, before washing.