Things You'll Need
Marble polishing cream
Steel wool pads (grades 2, 1 and 0)
If you love the look of marble and enjoy it in your home, then it is highly likely that you also get the dubious pleasure of enjoying this stone's susceptibility to water marks. The slightest delay in removing a sweaty glass from a marble countertop can result in serious "glass rings" that mar the beautiful look of your counters. Nearly always, unless the glass was actually made of some type of metal, the rings are not stains, but actually etching that has corroded the marble. Either way, you can often remove these rings.
Try lifting a mineral stain with white vinegar. Saturate a clean cloth with white vinegar and place it over the mineral stain for 60 seconds. This should lift up the minerals and after 60 seconds you should be able to wipe them away using gentle pressure from the clean, soft cloth.
Polish light water stains or etching away with marble polishing cream. If the etching is not deep, then you may be able to render it invisible by polishing the area of marble yourself. Use a marble polishing cream and the accompanying sponge to apply it. Buff according to the directions (brand-specific) with a soft cloth.
Remove the corroded surface yourself. This is risky and you will likely still have to bring in a professional to repolish your marble and potentially repair the damage that you yourself have done by abrading the corroded area of the marble. Use the steel wool in increasing orders (0, 1 then 2) to remove the corroded stone. If the 0 does not remove enough marble, then move to 1 and 2. Treat the scrubbed area with marble polish or have a professional repolish the area.
Have your glass rings treated by a professional. While this is not the cheapest way to deal with glass rings, it is generally your safest option if vinegar and marble polish do not do the trick.
Do not get marble countertops in your kitchen without implementing the proper protective measures, such as making sure that it is properly sealed from water and that you place glasses on wooden cutting boards or coasters every time you place them on the counter.