Classifying a stain by its origin
The stone trade puts identification before treatment, because the origin decides the mechanism — and three origins that look similar need three different answers.
In detail
The most consequential step in stain removal happens before anything is applied. The stone trade states it directly: identifying the type of stain on the surface is the key to removing it. Its own classification is by ORIGIN rather than by appearance, and each class carries a different mechanism. Oil-based stains darken the stone and normally must be chemically dissolved. Organic stains may leave a pinkish-brown mark. Metal stains must be removed with a poultice — drawn out rather than dissolved. Biological staining takes a diluted ammonia solution, with an emphatic warning never to combine it with bleach. The same principle governs every published stain sequence: the carpet trade's sequences diverge at the first step because a tannin, an oily soil, a protein and a particulate are different problems wearing similar marks. So the useful question is not how to get it out but what it is. A treatment chosen for the wrong class does not merely fail — heat sets a protein, acid etches carbonate, solvent spreads a pigment.
Why
- Poultice is explained by Classifying a stain by its origin
- Blotting is explained by Classifying a stain by its origin
- Perspiration is explained by Classifying a stain by its origin
Sweat is two problems filed as one. The odour is microbial and the fabric changes it; the yellowing is a stain for which no authoritative source gives a mechanism.
- Chimney sweeping is explained by Classifying a stain by its origin
- Fruit juice is explained by Classifying a stain by its origin
Sources for this page
Sources
Remove Stains from Stone Applications
Natural Stone Institute · Trade or professional body
Relied on for: That identifying the type of stain is the key to removing it, that oil-based stains darken the stone and must normally be chemically dissolved, that organic stains may leave a pinkish-brown mark, and that metal stains must be removed with a poultice. (states this directly)
Spot Solver: spot and spill removal procedures
The Carpet and Rug Institute (CRI) · Trade or professional body
Relied on for: That per-stain procedures diverge at the first step, with aqueous, solvent-first and mechanical-first branches for different classes of soil. (states this directly)