Marble surfaces are very porous, making it very difficult to keep them clean and to avoid damages. The best treatment will always be prevention, but in case of any accident, here are some tips on how to get rid of common stains on marble floors or tops.
If the stain is acidic (e.g. from juice or vinegar), you will need to apply to the stain a paste of baking soda and water, leaving it to dry. Then, just mop and wipe the surface.
If the stain is grease or oil, the first thing you will need to do is wipe the excess with a clean cloth. Apply corn flour to the area and leave it for one or two hours. After that just wipe with a damp soft cloth.
Marble surfaces can also be damaged by water. Leaving a wet glass on top of a marble table for a while can leave a mark that will darken the surface. On these cases, you can make a paste of 2 tablespoons of washing powder and 1/2 cup of warm water. Apply the mixture to the water stain. Rub the paste with a sponge and rinse with warm water, drying afterwards.