INTERACTIVE STAIN TREATMENT GUIDE

How to treat a host of stains on natural stone, tile and grout, concrete and terrazzo

About Stains

About Stains

STAINS COME FROM MANY SOURCES BUT MOST ARE REMOVABLE

The key to success is cleaning up any spills and treating any resulting stains as soon as you can. Understanding the source of the stain will help in determining the best treatment. Many options are available for treating stains on natural stone from creating your own poultice to using convenient ready-made poultices. Ask us for help if you need it.

We all know what a stain is…. or do we?

Let’s start by saying that a stain is a discoloration. So far, so good. The fact is, however, that not all discolorations are stains. To illustrate the point, let’s take, for example, a piece of common fabric. Fabric is typically absorbent. Therefore, if we spill some liquid onto it, the material will absorb it. If it is only water, it will leave a temporary stain. In fact, once it dries the fabric will go back to its original color, but if coffee or cooking oil is spilled on it a stain will occur because the fabric will absorb the staining agent and change its color in a permanent way—unless we do something to remove the agent from the fabric.

On the other hand, if bleach is spilled on that same fabric a discoloration will occur, but it can hardly be defined as a stain because it is actually a permanent damage to the dye that originally made the color of the fabric.

As with the fabric example, when it comes to natural stone there are stains that are true stains and there are “stains” that are actually discolorations caused by something else.

All stones are, more or less, absorbent. One may say that diamonds or gemstones are not absorbent. That’s right, but a gemstone is not actually a stone. It is actually made of one crystal of one single mineral.

All other (less noble) stones are the composition of many crystals, either of the same mineral, or of different minerals bonded together. The “space” in between these molecules of minerals is mostly what determines the porosity of a stone. The porosity of stone varies greatly, and so does, of course, their absorbency. Some of them are extremely dense, therefore their porosity is minimal. What this translates into is the fact that the absorbency of such types of stone is so marginal that—by all practical intents and purposes—it can be considered irrelevant. Some other stones present a medium porosity, and others at the very end of the spectrum are extremely porous. Because of their inherent porosity, many stones will absorb liquids, and if such liquids are staining agents a true stain will occur.

IS IT REALLY A STAIN?

A true stain is always darker than the stained material. If it appears as a lighter color it is not a stain, but either a mark of corrosion (etching) made by an acid, or a caustic mark (bleaching) made by a strong base (alkali). In other words, a lighter color “stain” is always surface damage and has no relation whatsoever with the absorbency rate of the damaged material—stone or otherwise. There is not a single exception to this rule.

A stain is a discoloration of the stone produced by a staining agent that was actually absorbed by the stone. Other “discolorations” have nothing to do with the porosity (absorbency) of the stone, but rather are a result of damage to the stone surface. All those “stains” that look like “water spots” or “water rings” are actually marks of corrosion (etches) created by some chemically active liquid (mostly—but not necessarily limited to—acids), which had a chance to come in contact with the stone. All calcite-based stones such as marble, limestone, onyx, travertine, etc., are sensitive to acids. Therefore, they will etch readily (within a few seconds). Many slates, will also etch and so will a few “granites” (those that instead of being a 100% silicate rock are mixed with a certain percentage of calcite).

Now let’s discuss how to remove stains!

How to remove a stain—Poulticing method

Definition of a Poultice

What’s a poultice? It is the combination of a very absorbent medium (it must be more absorbent than the stone) mixed with a chemical, which is to be selected in accordance with the type of stain to be removed. The concept is to re-absorb the stain out of the stone. The chemical will attack the stain inside the stone, and the absorbent agent will pull them both out together. The absorbent agent can be the same all the time, regardless of the nature of the stain to be removed, but the chemical will be different—in accordance with the nature of the staining agent—since it will have to interact with it. The absorbent part of a poultice could be (in order of preference): talcum powder (baby powder), paper towel or diatomaceous earth (the white stuff inside your swimming pool filter) for larger projects. NOTE: There are convenient poulticing kits that make the task of stain removal easier. You may want to ask your stone care contractor for some specific recommendations.

As we said before, the chemical must be selected in accordance with the nature of the staining agent.

There are five major classifications of stains:

Organic stains (i.e. coffee, tea, coloring agents of dark sodas and other drinks, gravy, mustard, etc.)

Inorganic stains (i.e. ink, color dies, dirt—water spilling over from flower or plant pots, etc.)

Oily stains (i.e. any type of vegetable oil, certain mineral oils—motor oil, butter, margarine, melted animal fat, etc.)

Biological stains (i.e. mildew, mold, etc.)

Metal stains (i.e. rust, copper, etc.)

The chemical of choice for both organic and inorganic stains is hydrogen peroxide (30/40 volumes, the clear type—available at your local beauty salon. The one from the drugstore is too weak, at 3.5 volume).

Sometimes, in the case of ink stains, denatured alcohol (or rubbing alcohol) may turn out to be more effective.

For oily stains, our favorite is acetone, which is available at any hardware or paint store. (Forget your nail polish remover. Some of them contain other chemicals, and others contain no acetone whatsoever.)

For biological stains, one can try using regular household bleach or a mildew stain remover designated safe for stone.

For metal/rust stains, our favorite is a white powder (to be dissolved in water) called Iron-out™, which can be found in any hardware store. There is also a product called RSR-2000 made by Alpha Tools (available at www.stonecarecentral.com) that is used and recommended by restoration contractors.

A poultice is an absorbent material applied to a surface to draw out a stain. It can be a powder, paper or a gel. The most common poultices in use today are powders. A number of powders are very absorbent and are ideal for stain removal. Some typical powders used in poultices are listed below:

Stonecare PRO Signature Professional Stone Poultice Powder
Clays and fullers earth
Talc
Chalk (whiting)
Sepiolite (hydrous magnesium silicate)
Diatomaceous earth
Methyl cellulose
Flour

Do not use whiting or clays containing iron. When using acidic chemicals the acids will react with the iron and may cause yellowing of certain stone surfaces. It is best to purchase poultice powder materials from a reputable supplier of products for this purpose.
There are also pre-packaged ready to use poultices such as Dr Fred's Innovative Solutions Stain Sponge www.godrfred.com.
Paper poultices can be quite effective on mild stains. They are easier to apply than powder poultices and are also easier to remove. Some typical paper poultices listed below:

Cotton balls
Paper towels
Gauze pads

Gel poultices are usually thick chemical gels that are designed to be applied to a stain with the use of powders or papers. They work effectively with certain stains. When purchasing poultice materials, ask if they contain stain removing chemicals or if they need chemicals added. Some powder and gel poultices contain chemicals, and all you need to do is add water. Never mix additional chemicals with a poultice that contains its own chemical formulation.

IMPORTANT

• Always read the label on the chemical bottle.

• Always follow the directions and precautions listed on the label.

• Never use a chemical if you are unsure what it is or how to protect yourself.

• Always take the time to protect yourself and those working around you.

• Always dispose of a chemical properly. Every municipality has a household hazardous waste drop-off location. For safe disposal of chemical products at work, contact your health and safety representative.

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Stain Management App

About Stains

About Stains

What is a Poultice?

What is a Poultice?

How to Apply a Poultice

How to Apply a Poultice

ADHESIVES

ADHESIVES

ALKALINE ETCHING

ALKALINE ETCHING

ALUMINUM

ALUMINUM

COLAS

COLAS

BLOOD

BLOOD

Unknown Stain

Unknown Stain

BODY FLUIDS

BODY FLUIDS

BURNS

BURNS

CANDY (NON-CHOCOLATE)

CANDY (NON-CHOCOLATE)

CARPET PADDING

CARPET PADDING

CHOCOLATE

CHOCOLATE

COFFEE AND TEA

COFFEE AND TEA

COPPER

COPPER

EFFLORESCENCE

EFFLORESCENCE

EGG

EGG

FATTY OILS

FATTY OILS

FURNITURE POLISH

FURNITURE POLISH

GLUE (SYNTHETIC)

GLUE (SYNTHETIC)

GLUE (WATER SOLUBLE)

GLUE (WATER SOLUBLE)

GRASS

GRASS

GREASE

GREASE

GUM

GUM

HARD WATER STAINS

HARD WATER STAINS

HEEL MARKS

HEEL MARKS

ICE CREAM (NON-CHOCOLATE)

ICE CREAM (NON-CHOCOLATE)

INK

INK

INK-TONER

INK-TONER

IODINE

IODINE

JAM OR JELLY

JAM OR JELLY

KOOLAID

KOOLAID

LEATHER

LEATHER

FRUIT JUICE (LIGHT COLORED)

FRUIT JUICE (LIGHT COLORED)

LIPSTICK

LIPSTICK

LIQUOR

LIQUOR

LOTION

LOTION

MAKE-UP

MAKE-UP

MILDEW STAINS