Oil-Based Stains: Grease, tar, cooking oil and food stains.
Organic Stains: Coffee, tea, fruit, tobacco, cosmetics, etc.
Metal Stains: Iron (rust), copper, bronze, etc.
Biological Stains: Algae, mildew, lichens, etc.
Ink Stains: Magic marker, pen, ink, etc.
2. 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. In other words, 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.
3, Apply the poultice to the stain being careful not to spill any on the non stained areas. Apply approximately 1/4-inch thick over-lapping the stain area by about one inch.
4. Cover the poultice with plastic (food wrap works great). Tape the plastic down to seal the edges. It also helps to poke several small holes in the plastic so that the powder will dry out. Failure to do this may result in the poultice staying wet.
5. 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.
6. 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 up to five applications for difficult stains.
Some chemicals may etch marble and limestone surfaces. If this occurs, then apply polishing powder and buff with a piece of burlap to restore the shine.
Sepiolite (hydrous magnesium silicate)
Clays and diatomaceous earth are usually the best. Do not use whiting or iron-type clays, such as Fullers Earth, with acidic chemicals. They will react with the material, canceling the effect of the poultice.
Iron (rust) - Poultice with Iron Out + Powder + Water. (Iron Out is available at hardware stores). Both mixtures may etch polished marble, so re polishing will be necessary.
Ink - Poultice with Mineral Spirits or Methylene Chloride +Powder.
Oil - Poultice with Ammonia+ Powder Methylene Chloride can also be used on tough oil stains.
Coffee, Tea & Food - Poultice with 20 percent Hydrogen Peroxide + Powder.
Copper - Poultice with Ammonium Chloride + Powder
Paint (water-based) - poultice with a commercial paint remover + Powder
Paint (oil) Poultice with Mineral Spirits + Powder. Deep stains may require Methylene Chloride.