Things You'll Need
3 percent hydrogen peroxide
Granite, limestone, soapstone and marble are four natural stones used in sinks. Stone sinks are elegant, durable and often expensive-- but with proper care and cleaning, they will last a lifetime. Since stones are naturally porous, certain items--such as food, beverages and cooking oil--can seep into the stone's pores and leave unsightly stains. General cleaning typically will not remove these tough stains. Instead, you must create a poultice that is safe for all natural stones and will pull the stain out of the pores.
Fill a container with 1 cup all-purpose flour. Slowly pour 2 tbsp. 3 percent hydrogen peroxide into the flour. Mix the contents together with a spoon.
Add 1 tsp. warm water to the mixture. Stir the contents together. Continue adding 1 tsp. warm water at a time until the mixture reaches a consistency of peanut butter.
Scoop some of the mixture with a plastic spatula. Spread a layer of the mixture 1/4 inch thick over the stains. Spread the mixture a few inches out from the tough stains.
Place a piece of plastic wrap over the mixture and secure the edges down with tape. Let the poultice sit on the stone sink for 24 hours.
Remove the plastic wrap and discard. If the poultice is still wet, replace the plastic wrap and let dry completely before continuing.
Rub the poultice off the stone sink with a sponge dampened with cool water. Continue rubbing until you have removed all traces of the poultice.
Wipe the stone sink clean with a cloth dampened with warm, soapy water. Rinse with cool water and wipe dry with a towel.
Repeat the process until you have removed the tough stains from the stone sink.
Do not use highly abrasive cleaners, metal scouring pads or ammonia on stone sinks. These items will dull your sink. If you are unsure about how the poultice will react to your stone sink, test a small amount of it on an inconspicuous area of the sink. If damage or discoloration occurs, discontinue use.