Rust Stained Limestone Sink Area
Rust stains, caused by iron oxide, can be one of the most difficult stains to remove from natural stone. San Diego homeowners called us because they had rust stains on their limestone countertop near the sink and around the faucet area. They were afraid the reddish-brown stains had permanently set into the stone.
Our Rust Stain Removal Process
First, we applied a solution of rust remover and water, agitated the area with a soft bristle brush, and then rinsed to remove much of the surface stain. (The chemicals in the rust remover caused etching, which was not an issue as we were already planning on honing and polishing the stone.)
To remove the rust that had penetrated into the stone, we mixed hydrofluoric acid and poultice powder, applied the mixture to the stone, covered it with plastic with holes poked to allow moisture to escape, and then instructed the homeowners to leave it alone until it was completely dried.
After the poultice dried, we refinished the limestone. We were able to remove the stain, almost completely. Once the new faucets are installed, no one will ever know there used to be rust stains there.