Marble is stone that is generally polished and used in fine building work, furniture, or decorative art. Marble is porous, and easily stained. Wipe off anything spilled on marble immediately, as you would on a wood surface. Seal the marble with paste or sealer to prevent stains and soil from being absorbed into the porous surface. Acids that contact marble will etch it, while strong alkaline solutions are absorbed by the marble and break down the surface leaving it rough. If well-sealed, damp-mopping should keep it clean.