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Removing Stains From Stone
Removing stains from granite and marble can prove difficult. There are,
however, several precautionary measures you can take:
Any spill should be cleaned as soon as possible. Blot spills with a paper towel
or clean rag. At this stage, it is important only to blot; wiping a spill may
spread it over a larger area, making a larger mess. Use only cold water and
stone soap or a neutral cleaner. Rinse the area several times. If a stain is
still present, a chemical poultice may have to be applied.
Avoid using chemicals of any kind until you know which chemical cleaner to use.
(See "Choosing a Chemical" below) Certain chemicals will react with
the spilled material and could make the stain permanent. to the top
Granite and marble are porous materials. If not thoroughly sealed, they will
stain. The only way a stain can be removed is to literally pull it out of the
stone or ceramic with both a chemical and material that will absorb the stain.
This chemical absorbent-material combination is what we call a poultice.
Poultices are commonly powder or cloth materials that can be mixed with a
chemical and placed on top of the stain. Refer to the table below for some of
the more common poultice materials. Clays and diatomaceous earth are safe and
readily available, but do not use whiting or clays containing iron with an
acidic chemical; iron will react with the acid, and may cause rust staining. It
is best to purchase powders that are designed specifically for stone and tile.
Consult a stone restoration specialist or your stone supplier if in doubt.
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Poultice materials:
Paper towels
Cotton balls
Gauze pads
Clays such as Attapulgite, Kaolin, Fuller's Earth
Talc Chalk (whiting)
Sepiolite (hydrous magnesium silicate)
Diatomaceous earth
Methyl cellulose
Flour
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How to apply a poultice
Before you attempt to remove a stain, it is extremely important to know
what has caused it. If you don't know, I would recommend that you consult a
stone specialist, or refer to my book on stain removal for a detailed
description of the procedure.
To apply a poultice, take the following steps:
1. Clean the stained area with water and stone soap. Remember to blot rather
than wipe.
2. Pre-wet the stained area with a little water. Distilled water is
recommended.
3. Refer to the chart below and determine which chemical to use for the stain.
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4. Mix the poultice material with the selected chemical. Mix until a thick
peanut-butter paste consistency is obtained.
5. Apply the paste to the stained area, overlapping the stain by at least
¼". Do not make the application too thick, or it will take a long
time to dry.
6. Cover the paste with a plastic sandwich bag or food wrap. Tape the plastic
using a low-contact tape.
7. Allow the paste to sit for 12–24 hours.
8. Remove the plastic cover and check to see if the paste has dried. If it has
not, allow it to sit uncovered until thoroughly dry.
9. Once it is dry, remove the paste by scraping and rinse the area.
10. Examine the stain. If it still remains, but is somewhat lighter,
re-poultice until it is gone. If the stain refuses to disappear completely, it
is time to give up, replace the tile or call a stone specialist.
Stain removal can be very difficult, and care must be taken when using a
poultice.to the
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Choosing a Chemical
| Stain |
Poultice with |
| Rust |
Iron Out |
| Coffee and tea |
Hydrogen Peroxide |
| Ink, magic marker, etc. |
Methylene Chloride (use with extreme care) |
| Oil |
Ammonia or a degreaser |
| Paint |
Mineral Spirits |
A product called
Iron
Out is available from most home centers and hardware stores. This product
is a white powder that is designed for removing iron from water softeners, but
also works great for removing iron and other metal stains from stone. To remove
iron stains mix I part Iron Out to 2 parts poultice powder (diatomaceous
earth). Add water until you get a soupy consistency. Apply this mixture to the
iron stain, cover with plastic and let it sit for 24 hours. After 24 hours
remove the poultice and reapply if necessary. Please use extra
caution when handling all chemicals listed above. Thoroughly read Material
Safety Data Sheets for each chemical before use.
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