Poultice
A paste left on a stain for a day or two to draw it back out of a porous material. One of the few methods measured in hours rather than seconds.
In detail
A poultice reverses the direction a stain travelled. The stone trade defines it precisely: a liquid cleaner or chemical mixed with a white absorbent material to form a paste about the consistency of peanut butter, spread over the stain to a thickness of about a quarter to a half inch, covered, and left for 24 to 48 hours while the cleaner draws the stain into the absorbent material. Every element of that is doing work. The cleaner dissolves or loosens what is in the stone; the absorbent holds it; the covering stops the paste drying before the transfer happens; and the time is what allows a slow migration out of a material the stain took time to enter. WHITE absorbent is specified because a coloured one would deposit its own dye. It is the method for a stain sitting INSIDE a porous material rather than on it, and it is the same capillary transport that makes cornstarch work on suede oil, run longer and with a solvent in the paste. Two cautions: whiting or iron-type clays must not be used with acid chemicals, and deep-seated stains go to a professional restorer.
What works
Poultice is effective against Oil and grease on textile Supported
Why
- Poultice is explained by Capillary absorption
- Poultice is explained by Classifying a stain by its origin
- Poultice is explained by Penetration into fibres
- Poultice is explained by Capillary absorption
Sources for this page
Sources
Remove Stains from Stone Applications
Natural Stone Institute · Trade or professional body
Relied on for: That a poultice is a liquid cleaner mixed with a white absorbent material to a peanut-butter consistency, spread a quarter to a half inch thick, covered and left 24 to 48 hours while the cleaner draws the stain into the absorbent, and that metal stains must be removed with a poultice. (states this directly)
Leather Care and Cleaning Guide
The Leather Institute, 2011 · Trade or professional body
Relied on for: That cornstarch placed over an oil mark and rubbed until it coagulates with the oil draws the oil out of the material. (applied to this case rather than stated directly)