Many natural stone owners are aware that acids like vinegar, lemon, etc. can cause etching, but did you know high alkaline substances can also cause etching?
See Fred Hueston, Chief Technical Director of Stone & Tile PROS, demonstrating how to mix and apply a poultice for removing a stain from natural stone.
Should stone in wet conditions be sealed? In the following article, industry expert, Fred Hueston explains why stone in wet areas should not be sealed.
Darkness from moisture in a poultice application can wick out beyond the original stained area. This is not a stain, and the problem is easy to resolve.