Marble stone countertops as one calcareous stone is sensitive to the acid chemicals and solutions, so remember do not use any splash of lemon juice or acid spill on the surface, which will easily leave subtle mark on the countertops.
So, how to clean and maintain marble stone countertops? It is not hard for you to do that. Just take some warm water and soft soap mixed in one bowl, then fill a spray bottle with it, spray the countertops lightly, and then use one dry cloth to wipe it and one clean cloth dry off.
For marble flooring cleaning, you need one mop with clean rag. If you prefer to vacuum, then make sure each part of your vacuum is in good condition to protect the surface from scratching. In daily life, you can also use one mats or rugs to minimize the dust and dirt on the floors.
It is great for your marble stone countertops sealed, but that just make the surface more resistant, not proof. So it is the important thing to make sure the stain type to remove it. If it is oil-based stains, there are some good liquid cleaner recommended for you, namely household detergent, mineral spirit and acetone. While when there is coffee, tea and wine on the surface, then just wipe them immediately to avoid the marks.
Finally, if the surface has deep scratch, then you had better ask a professional for help.