QUESTIONOur granite kitchen counter has brown stains in the narrow area between two sinks that we believe are caused by mineral deposits from sitting water in this area. We have tried poultices (covered with plastic, taped down, thoroughly dried) with white vinegar and with bleach and had no results. Any suggestions?
ANSWERANSWER - There are many different types of stains, so the trick is to try to determine what caused the stain, because if you know that, then you have a chance at figuring out how to remove it.
Since the stain is between the two sinks there is a good chance that there is a metal clip or frame below or near where the staining is occurring. Water from using the sinks probably collects on top of the granite between the two sinks. If the transition between the stone and the sinks are not properly caulked (sealed) with a proper ASTM C920 sealant then mater might be migrating beneath the stone and causing the rust or brownish stains. Sometimes if the stains have started from below it may be difficult if not impossible to remove.
Stains are normally related to the stone being subjected to either excessive moisture or to some other liquid or material. When there is excessive moisture coming from either above the stone or from below the stone it can cause iron staining. Many natural stones have iron oxide within it that can rust and cause a stain. If there is metal under the stone or embedded in the stone and water comes into contact with the metal it can cause staining. There are other types of stains too, which could be from hair dye or other liquids.
There are poultices that can be used to pull the stain out of the stone. Depending on the type of stain the poultice is prepared to penetrate into the stone and loosen up the stain, and then draw the stain up into the poultice. A poultice is a chemical or mixture of chemicals combined with an absorbent material to form a thick paste, which is applied to the stone to remove stains. Without having the right experience, it is difficult to determine how to prepare the poultice for your situation.
Best bet is to hire a professional stone restoration company who has a lot of experience to help determine how to remove the stain. Otherwise you could go online and look for premixed poultices produced and sold by companies who make cleaners for stone. Go to the CTaSC website to the Cleaners and Sealers Resource section to see a list of companies who provide cleaners: Cleaners and Sealers.