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will occur, but it can hardly be defined as a stain because it is actually a permanent damage to the dye that originally made the color of the fabric.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.
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).
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. Now let's discuss how to remove stains!
HOW TO REMOVE A STAIN
A poultice is the best way to break down and draw out a stain on stone or other hard porous surfaces.
WHAT IS A POULTICE?
A poultice 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 PRO for some specific recommendations.
As we said before, the chemical must be selected in accordance with the nature of the staining agent.
5 CLASSIFICATIONS OF STAINS
1. Organic stains (i.e. coffee, tea, coloring agents of dark sodas and other drinks, gravy, mustard, etc.)
2. Inorganic stains (i.e. ink, color dies, dirt-water spilling over from flower or plant pots, etc.)
3. Oily stains (i.e. any type of vegetable oil, certain mineral oils-motor oil, butter, margarine, melted animal fat, etc.)
4. Biological stains (i.e. mildew, mold, etc.)
5. Metal stains (i.e. rust, copper, etc.)
The chemical of choice for both organic and inorganic stains is hydrogen peroxide (30/40 volume, 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.
ABOUT THIS APP
Created by SurpHaces, the surface care experts, with Chief Technical Director Fred Hueston
SurpHaces, the experts in surface care, in collaboration with Chief Technical Director, Fred Hueston, internationally renowned expert in natural stone restoration, has developed this comprehensive, but simple to use, stain management app. The program features a database of the most common types of stains you will encounter on natural stone or other hard porous surfaces with step-by-step instructions for treating them, as well as a how-to video for making and applying a poultice.
For stains or other surface damage you cannot resolve, contact your SurpHaces PRO Partner.
Copyright 2021 SurpHaces, LLC DeBary, FL. All Rights Reserved.
How to Create and Apply a Poultice
STEPS FOR CREATING AND APPLYING A POULTICE
1. Identify the stain.
2. Clean the stained area to remove excess from the surface.
3. Wet the stained area with distilled water. Pre-wetting fills the pores of the stone with water, isolating the stain and accelerating the removal by the chemical.
4. Prepare the poultice. If a powder is to be used, pre-mix the powder and the chemical of choice into a thick paste the consistency of peanut butter. Wet it enough so that it does not run. If a paper poultice is to be used, soak the paper in the chemical. Lift the paper out of the chemical until it stops dripping.
5. Apply the poultice to the stain, being careful not to spill any on the un-stained areas. Apply poultice approximately one-quarter-inch thick, overlapping the stain area by about one inch.
6. Cover the poultice with plastic (food wrap works very well). Tape the plastic down to seal the edges. Allow the poultice to dry thoroughly. This is a very important step. The drying of the poultice is what pulls the stain from the stone into the poultice material. If the poultice is not allowed to dry, the stain may not be removed. Drying usually takes from 24 to 48 hours.
7. After 24 to 48 hours, remove the plastic.
8. Remove the poultice from the stain. Rinse with distilled water and buff dry with a soft cloth. If the stain is not removed, apply the poultice again. It may take five applications or more for difficult stains.
9. Some chemicals may etch the marble surface. If this occurs, apply a polishing powder and buff to restore the shine.
For further assistance, contact your SurpHaces PRO Partner.
Search stain database
STEPS TO TREATING STAINS
- The most important step is to identify the stain. Once the stain is identified look it up in the Stain Database
- Once the proper chemical is selected, prepare your poultice. Refer to the How-To Video. Be sure to wear gloves and eye protection when using any chemical.
- Once a stain is clearly identified, the steps to remove it can begin. These should be followed in numerical order, and close attention should be paid to the cautions for certain situations.
- Always read the label on any chemical bottle.
- Always follow the directions and precautions listed on the lablel.
- 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 chemicals properly. Every municipality has a household hazardous waste drop-off location. For safe disposal of chemical product at work, contact your health and safety representative.
- Thoroughly clean the area with water and a mild detergent.
- Once the area has dried, pour some 40 volume hydrogen peroxide on a clean white rag and rub the stained area.
- If stain remains, use a poultice with 40 volume hydrogen peroxide.
Types: Tape residue, cellophane, stickers, etc.
Problem: Sticky residue on surface of stone. Some tape residues, especially duct tape can penetrate below the surface of the stone and can be very difficult to remove.
- Peel off any remaining tape. Use a very sharp razor blade and be careful not to scratch the surface of the stone.
- The remaining sticky residue can usually be removed with a rag and acetone. Pour the chemical on a clean white rag and rub the area until all of the sticky residue is gone.
- If the adhesive has left a stain, prepare a poultice of mineral spirits and poultice powder, being careful to follow directions for all user and label precautions.
Type: Etching from alkaline strippers, ammonia, or heavy duty stone cleaners
Problem: Alkaline etching is caused by alkaline salts contained in cleaners that are deposited below the surface of the stone. The etch marks appear similar to an acid etch mark.
- Attempt to remove the etching with a mild acid such as vinegar.
- If dealing with a polished marble, re-honing and re-polishing may be necessary. Contact your stone restoration PRO.
Type: All aluminum, usually from windows, awnings, etc.
Problem: Can leave a crusty, whitish residue.
- Remove any crusty residue from surface. On polished surfaces, use a sharp razor blade. On textured surfaces use a hard brush.
- On polished surfaces, dilute hydrochloric acid in 40 parts water. Apply the solution and agitate with a soft nylon brush.
- On textured surfaces, mix hydrochloric acid in 20 parts water. Apply the solution and agitate with a soft nylon brush.
(Be extremely careful with acids on or near marbles; they will severely etch the surface requiring professional honing and re-polishing.)
- Clean the entire area thoroughly with water and a mild detergent. Allow the water and soap to soak into the stone for several minutes. Lightly agitate the area and remove excess water with a dry towel. Rinse the area with clear water.
- If the above cleaning procedure does not remove the beer stain, try a 50/50 mix of ammonia and water.
- If the stone is still stained, prepare a poultice with 40 volume hydrogen peroxide.
- After you remove any solid material, wash the area with a neutral cleaner and a clean rag.
- If stains exist after this, make a poultice with 40 volume hydrogen peroxide.
Bird droppings contain uric acid and may result in etching on some stones. If this happens, you may need to have the finish professionally restored.
Types: Human and animal blood and raw meats prepared on a marble countertop can cause blood staining
Problem: Blood contains salts and proteins; if it is cleaned while still fresh it will usually not stain. If allowed to dry, blood stains can be very difficult to remove.
- Clean the area thoroughly with cold water and a mild dish detergent.
- Prepare a 50/50 solution of household ammonia and water. Apply this solution and allow to sit for several minutes. Gently scrub the area and rinse with cold clear water.
- If stain is still present, poultice with poultice powder and ammonia.
Types: Cigarette, hot irons, propane, etc.
Problem: Cigarette and cigar burns will leave a yellow nicotine stain which can be difficult to remove. Cigarette burns can also melt the stone and in the case of granite may cause spalling.
- If the stone is melted or spalled, professional re-honing and polishing will be necessary.
- If a yellow nicotine stain is the problem, poultice with 40 volume hydrogen peroxide and poultice powder.
- If several poultice applications do not work, try a poultice with mineral spirits.
Problem: Candle wax can present a few issues. The candle wax may have melted onto the surface and into the pores of the stone and will need to be removed. If the candle has dye in it any staining has been left behind, that will need to be treated.
- Begin by scraping any solid wax material from the surface of the stone with a plastic scraper. Avoid using metal or any tool that can scratch the stone.
- To remove candle wax that melted into the pores of the stone: Use a hot clothing iron (preferably one you don’t mind getting wax on) and white paper towels to melt and lift any remaining wax. Place the paper towel over the stain and iron it with the hot iron. As the wax softens, it will be absorbed by the paper towels. Be sure to use new paper towels as needed.
- Removing residual stains: After you have scraped the wax off and used the iron and paper to absorb embedded wax, soak a clean cloth in water, wring it out and apply a few drops of Reagent #2 (or degreaser or ammonia).
- Wipe the stone with the cloth to eliminate the remaining candle residue. Finish by rinsing the surface with water and air dry.
- . If any staining remains you will need to use a poultice to break down and draw out the stain. Try a poultice with Reagent #1 (or 40 volume hydrogen peroxide).
- If that doesn’t work after a couple of tries, try a poultice using Reagent #2 (or paint thinner) as your chemical.
Types: Myriad types of candies, all containing sugar and various dyes.
Problem: Several candies contain dyes; red dye especially can be very difficult to remove.
- Scrape remaining candy from surface.
- Clean area with Reagent#2 (or acetone) and a clean white cloth.
- If Reagent #2 (or acetone) doesn’t work, poultice with poultice powder with Reagent #2 (or mineral spirits)
Types: Candy, cocoa, ice cream
Problem: Can leave brown stains on light colored marbles
- Clean area thoroughly with cold water and a mild detergent.
- If stain is still present, clean with ammonia and water. Let solution sit on stained area for several minutes. Remove excess solution and rinse with clear cold water.
- If above procedure fails, poultice with 40 volume hydrogen peroxide and poultice powder.
COFFEE AND TEA
Types: All coffee including instant coffee, hot tea and iced tea
Problem: Coffee and tea both contain tannin which can leave a yellow to brown stain. If left on stone long enough the stain can penetrate deeply and be nearly impossible to remove. If the concentration of coffee or tea is strong enough it can also etch the surface of polished marble. When this happens you will need to have your stone restoration PRO restore the finish.
- Pour 40 volume hydrogen peroxide directly on the stain and add a few drops of ammonia. Leave until any bubbling stops.
Caution: Do not use ammonia only. Ammonia can permanently set the stain.
- If the above procedure does not remove the stain, poultice with a poultice powder and 40 volume hydrogen peroxide.
- If all else fails, poultice with mineral spirits and poultice powder.
Type: Copper piping, sculptures, etc.
Problem: Copper can cause a green stain that can sometimes penetrate deep into stone if allowed to age.
- Remove any excess crust by scraping with a sharp razor blade. If the surface is polished, wet the surface with soap and water to prevent scratching the stone.
- Prepare a solution of 1 part ammonia and 3 parts warm water. Apply this solution to the surface and agitate with a soft bristle brush. Rinse with clean water.
- If the stain is still present, poultice with ammonia and poultice powder.
Types: Chicken or duck
Problem: Eggs contain a protein called albumin which can leave a yellow stain.
- Clean area thoroughly with cold water and a mild detergent or stone soap. Caution: Do not use hot water as it can set the stain.
- If stain still remains, poultice with poultice powder and Reagent #1 (or 40 volume hydrogen peroxide)
Types: Butter, margarine, fried foods, mayonnaise, salad dressings, gravy, etc.
Problem: Fats and oils can leave a dark stain which can be difficult to remove. Some salad dressings and foods contain dyes which can also cause staining.
- Thoroughly clean stained area with cold water and a mild detergent or stone soap.
- Apply a commercial degreaser to the stained area and let sit for several minutes. Remove excess and rinse with clean, clear water.
- If stain is still present, poultice with a commercial degreaser and poultice powder.
FRUIT JUICE (LIGHT COLORED)
Types: Apples, pears, oranges, lemon, lime, grapefruit and their juices
Problem: The acids in some fruits, especially lemon will etch polished marble. The sugars in these fruits will turn yellow or brown if allowed to sit too long.
1. If the surface is etched, re-polish using a quality marble polishing compound. If the etching is very deep, re-honing may be necessary.
2. If the fruit has left a stain then clean the area with cold water and a mild detergent.
3. If stain still remains poultice with poultice powder and 20-50% hydrogen peroxide.
Types: Spray and liquid furniture polishes
Problem: Oils, dyes, waxes and silicones can cause staining. The darker polishes (e.g., walnut) can permanently stain the stone.
1. Clean with acetone and a clean white rag. Allow acetone to sit on stain area a few minutes and blot remaining acetone with a clean rag.
2. If stain is still present, poultice with poultice powder and mineral spirits or commercial paint remover.
GLUE (WATER SOLUBLE)
Types: Casein, mucilage, paste and hide glue
Problem: The white and clear glue rarely stain. However, some of the darker glues can leave a stain that can be difficult to remove.
1. Scrape excess glue with a sharp razor blade. Be careful not to scratch the surface.
2. Clean with cold water and a mild detergent. Try using a green scouring pad.
3. If glue is stubborn, use acetone and a clean white rag.
4. If the glue has left a stain, poultice with poultice powder and mineral spirits.
Types: Super glue, hot glue, epoxy resin, plastic model cement
Problem: These types of glues will rarely stain. The glues are usually hard to remove from the surface.
1. On smooth surface, scrape glue with a sharp razor blade. Be careful not to scratch the surface.
2. Any remaining residue can be cleaned with acetone and a clean white rag.
3. If the glue is really stubborn, soak the area in acetone for several minutes then try scraping with a razor blade, followed by wiping with acetone.
Type: Grass Stain
Problem: Tannin and chlorophyll in the grass can leave a nasty green or yellow stain.
1. Clean stained area with a clean white rag and denatured alcohol.
2. If stain still remains, poultice with poultice powder and 20-50% hydrogen peroxide.
Caution: DO NOT use ammonia, or any alkaline cleaners on grass stains – it can permanently set the stain.
Types: Petroleum type grease such as wheel bearing grease, cooking grease, vegetable oils, etc.
Problem: Can leave a nasty dark stain that can penetrate deeply into the stone. Can be very difficult to remove. Try to remove as soon as grease is spilled.
1. Clean area thoroughly with cold water and a mild detergent.
2. Soak stained area with a commercial degreaser for several minutes. If degreaser solution dries, reapply, keeping it wet. Remove excess degreaser and rinse with clean water.
3. If stain is still present, poultice with poultice powder and commercial degreaser.
4. For stubborn grease stains, poultice with poultice powder and mineral spirits or commercial paint remover.
Types: Chewing gum, tree gum (sap), etc.
Problem: Gum rarely stains polished stone surfaces but can be very difficult to remove from honed and rough textures surfaces.
1. Do not try to scrape gum off surface; this only makes more of a mess. Freeze the gum using an aerosol gum freeze, available at most janitorial supply houses. Spray the gum for several seconds, then chip the gum with a scraper or putty knife. This should remove most of the gum.
2. If there is any gum residue still remaining, apply a solvent cleaner such as a dry spotter, also available at most janitorial supply houses.
HARD WATER STAINS
Types: Water stains from irrigation systems, faucets, bathroom fixtures, shower walls, etc.
Problem: The minerals in water will leave mineral deposits which can appear as a white haze or even large deposits of crust like minerals.
1. If deposits are large, try scraping off excess deposits with a sharp razor blade.
2. Clean with a heavy duty soap film remover.
3. If deposits still remain, apply a solution of weak phosphoric acid and agitate the area applying more acid as needed. NOTE: This will etch all marble surfaces, so plan on having to professionally refinish the marble.
4. Re-hone and polish the stone if necessary.
Some mineral deposits will be imbedded below the surface of the stone and may cause spalling. If this is the case, replacement of the damaged stone is the only alternative.
Types: Black rubber, neoprene
Problem: Rubber can leave a black streak mark on surface of stone. These marks rarely stain but can be difficult to remove from rough textured stones and concrete.
1. Clean with acetone and a clean white rag. On textured stone try using a green scrub pad with acetone.
2. If acetone doesn't work, then try another solvent such as dry spotter, available at a janitorial supply.
ICE CREAM (NON-CHOCOLATE)
Types: All flavors except chocolate (also see chocolate)
Problem: Food coloring and fruits can cause staining.
1. Clean area thoroughly with cold water and a mild detergent or stone soap.
2. If stain still remains, poultice with 20-50% hydrogen peroxide and poultice powder.
3. If the stain is very stubborn, try a poultice with mineral spirits or similar solvent and poultice powder.
Types: Ball Point pen, magic marker, carbon paper, newspaper print, etc.
Problem: Most inks penetrate deep into the stone and can be very difficult to nearly impossible to remove, depending on the age of the stain. It is very important to remove the stain as quickly as possible.
1. Clean the area thoroughly with acetone and a clean white rag.
2. Poultice the stain with a solvent such as mineral spirits or commercial paint remover and poultice powder.
3. Several attempts may be necessary to remove stain. If no improvement is noticed after 5 attempts, the stain is most likely permanent.
Type: Copy machine toner and similar inks
Problem: This is one of th