Wipe up any spills immediately so they won't penetrate the surface of the limestone countertop.
Wipe a limestone countertop daily with stone cleaner or a mixture of warm water and a few drops of mild liquid dishwashing soap.
Remove stains with a mixture of 1 cup flour, 2 tbsp. of mild dishwashing liquid and enough water to make a thick paste. Put the mixture on the stain without rubbing it in, and cover it with plastic wrap. Leave it overnight, scrape the mixture off with a rubber spatula or a wooden spoon, and rinse.
Clean oil-based stains with a mixture of 2 tbsp. hydrogen peroxide, 1 cup flour and enough water to make a thick paste. Continue as directed in Step 3. If the stain persists, substitute ammonia for the hydrogen peroxide.
Mix peroxide with a few drops of ammonia to remove tea, coffee or fruit stains. Wipe the mixture on with a soft cloth, and rinse immediately.