How is the stone cleaned if mortar gets on it during installation?
The first thing to note is prevention. By that, always be attentive to the texture of the mortar as it reaches a somewhat more dry, and crumbly level. It’s always easier to clean mortar at that stage rather than too soon (wet mortar), or too late (hard mortar). If an area is missed, use a mild solution of warm water and tri-sodium phosphate with a stiff bristled brush. BE SURE TO NEVER USE ACID TO CLEAN THE STONE OR FACIAL COLORINGS WILL BE DAMAGED.
