NTC

The National Training Center for Stone & Masonry Trades

Stain Removal Guide

WHAT IS A POULTICE?

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 the following:

Clays and fullers earth

Talc

Chalk (whiting)

Sepiolite (hydrous magnesium silicate)

Diatomaceous earth

Methylcellulose

Flour

Clays and diatomaceous earth are usually the best. 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 reputable suppliers of products for this purpose. Some typical paper poultices are:

Cotton balls

Paper towels

Gauze pads

Paper poultices can be quite effective on mild stains. They are easier to apply than powder poultices and are also easier to remove. Gel poultices are usually thick chemical gels 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.