Marble & natural stone

Acids etch — blot, don't wipe, and use poultices for deep stains.

Etch marks come from acids left on the stone surface — do not use acidic cleaners on marble. [1]
Blot spills with a paper towel immediately; wiping spreads the spill. [1]
Deep-set stains are drawn out with a poultice — a paste about the consistency of peanut butter made from a cleaning agent and an absorbent powder, left to dry 24–48 hours and repeated as needed. [1]
The stone institute's own page carries an explicit warning: never mix bleach and ammonia — the combination creates a toxic and lethal gas. [1]

Sources

Industry body Natural Stone Institute — Stain Removal (Consumer Resources) (accessed 2026-08-18)

Updated 2026-08-18. Compiled from the cited sources; not independently verified by this site. Spotted an error? See the corrections policy.