• (p. pr. & vb. n.) of Poultice
(from the article `art conservation and restoration`) ...to soak, or secured to a site, other methods must be employed. Also, some stones are composed of minerals that themselves will readily dissolve ...
applying pastes, acid, alkaline or neutral to facades. See stone cleaning. 
Method of drawing soluble salts or stains out of stone by applying an absorbent such as clay or diatomaceous earth, mixed to a paste with water or cleaning solvent.