How to Remove Stains from Granite Countertops
Question: “How do I remove water stains from my black honed absolute granite counter tops?”
Removing stains from granite countertops can be both a challenge and a puzzle at the same time. In order to remove a stain, you need to ensure that it is indeed a stain and not damage to the stone. Next, you need to determine what caused the stain so that you can apply the correct materials to remove it. Here are guidelines for determining the problem and the necessary steps to resolve it.
Stain or Damage?
Use these guidelines to determine whether the spots you are seeing are in fact stains or if they are areas of damaged stone. If you are unsure, consult a professional before proceeding.
- Discoloration from the stone absorbing a staining agent (coffee, tea, oil, etc.)
- When the staining agent is removed, the stain is gone.
- A change in the natural chemical makeup of the stone.
- Not caused by the stone absorbing an agent, but rather caused by damage to the surface.
- Corrosion, typically caused by acids, leaving “rings” or “water spots” that cannot be removed.
- You cannot remove a “stain” that is actually damage as it requires repairing/removing the damaged area.
- It needs to be determined if the damage is to the stone or to the protective coating/sealant. (Some types of granite do not require sealants and when they are applied, they become damaged and look as though the area is stained.)
Removing Stains from Granite
Removing stains requires the use of a poultice. A poultice consists of two materials: 1) an absorbent material, such as Bounty or Viva paper towels, talcum powder or diatomaceous earth and 2) a chemical to remove the stain. There are five different categories of stains and each has its own designated chemical for the poultice.
Categories of Stain:
- Stains: Organic (coffee, soda, mustard, gravy, tea, etc.)
Chemical: Hydrogen Peroxide (30%-40% by volume)
- Stains: Inorganic (ink, dyes, dirt, etc.)
Chemical: Rubbing Alcohol for ink; Hydrogen Peroxide (30%-40% by volume) for all others
- Stains: Oil (any type of cooking oil, some mineral oils, butter, margarine, etc.)
Chemical: Pure Acetone (avoid using nail polish remover as different brands have different ingredients)
- Stains: Biological (mold, mildew, etc.)
Chemical: Bleach or MB-9
- Stains: Metal (rust, copper, etc.)
Chemical: Iron-out (a white powder available at hardware stores)
The Removal Process:
Due to the nature of this removal process, you may want to test a small, inconspicuous area of the stone to ensure there are no adverse effects.
- Begin by mixing the poultice (ex: talc powder and hydrogen peroxide). You will want to create a thick paste. It should have the consistency of putty.
- Apply the mix to the stained area, keeping it only on the stain. The layer of paste should be about one fourth of an inch thick and overlap the stain about a half an inch.
- Cover the area with plastic wrap and tape the edges down. Allow it to set for 24 hours.
- Remove the tape and plastic wrap only, leaving the poultice in place.
- Allow this to remain on the stain until it is completely dry. This can take anywhere from a couple of hours to a couple of days.
- When the paste is completely dry, use a plastic scraper to scrape away the paste.
- Wipe remaining paste away with a clean cloth.
- Clean the area as normal and dry with another clean cloth.
- If the stain remains, you may need to repeat steps 2-6 several times, especially for oily stains, each time removing more of the stain.
Most water stains are only a temporary problem. The granite may darken or lighten in color when the water is absorbed into the stone. However, once the water evaporates, the color of the stone should return to normal. To prevent this absorption from happening in the first place, it is necessary to seal the surface of the granite with a high quality sealer. This can be completed on your own or by a professional.
If hardwater stains occur, they can be removed by applying vinegar to the area using the same methods as above.
Repairing Damage to Granite
It will require professional assistance to repair damaged stone. You can also consult the location where you purchased your stone for advice and service options.
This information has been adapted from the No-nonsense Guidelines to Stain Removal at www.findstone.com.