You’ve chosen marble for your countertops or floor. Brave decision. Marble is one of the most delicate surfaces to have in your home, even if it’s, well, stone.
According to the Marble Institute of America, “the first step in proper stone care and maintenance is to understand your stone’s geological classification and composition.”
Marble is classified as a calcareous stone. It’s composed mainly of calcium carbonate (just like shells and pearls). However, as Calcium Carbonate is sensitive to acidic solutions, any splash of lemon juice or other acidic spill will leave a subtle mark.
That’s why we need to warn you: do not, by any means, use vinegar on marble.
So, how can you clean your marble countertops?
Take a bowl and mix warm water and gentle dish soap (make sure that it doesn’t contain any kind of acid). Fill a spray bottle with it, and spray the counter lightly. Wipe thoroughly with a wet dish cloth. Dry off with a clean cloth.
Even the glasses and cups that contain an acidic solution can permeate its content to your marble and damage it. So, use coasters all the time.
If your marble is not on the kitchen countertops, but on your floors, you might want mop as frequently as possible. Remember to use a clean rag. If you use a solution, go for one that is mostly alkaline.
If you prefer to vacuum, make sure that every part of your vacuum is in good condition in order to avoid scratching the surface of the floor.
You can also use mats and rugs to minimize the quantity of dust and dirt in your floors, as they may scratch the stone.
You can say: yes, well, my marble is sealed. This is a great thing to have! But having a sealed marble doesn’t mean that it’s incorruptible, it just makes it more resistant.
So, when an accident occurs and you have an ugly stain in your stone, identifying the type of stain is the key to removing it.
Oil-based stains: Clean gently with a soft, liquid cleanser with one of the following: household detergent, mineral spirits, or acetone.
Organic: A coffee, tea, wine and similar kind of stains may cause a pinkish-brown stain. If your marble is in outdoors, time, sun and rain will remove it, if the case is inside your house, clean with 12% hydrogen peroxide and a few drops of ammonia.
Ink/paint: Use hydrogen peroxide for clear colored stones. For dark colored ones, clean with lacquer thinner or acetone.
Water Spots and Rings: Hard water can accumulate and stain your marble. Buff with dry 0000 steel wool and your floor or countertop will be as good as new!
I have no stains, but scratches!
If your problem is scratches and nicks, you can follow the same steps as for the water stain: buff with dry 0000 steel wool. For deeper scratches and nicks ask for professional help.
Let us know your techniques to clean your marble stone at home!
 Found at https://marble-institute.com/consumers/care.cfm