Stone fireplaces are durable and energy efficient. The stones absorb heat from the fire and radiate it into the room, and they can remain hot for some time after the fire is out. These fireplaces also can accumulate soot, dust and burn marks. You can beautify and brighten a stone fireplace and add some protection to the stone and mortar by cleaning and sealing it.
Wear rubber gloves. Mix one pint of muriatic acid with a gallon of water in a five-gallon bucket. Carefully fill the trigger-sprayer bottle. Attach the trigger and pump a few sprays into the bucket to be sure that the sprayer functions.
Begin at the top of the stone fireplace. Spray the acid solution over a small area. Allow the acid to fizz and burn for one to two minutes. Scrub the area with an acid scrub brush to remove thick residue or stains.
Mix a cup of ammonia with a gallon of water. Fill a trigger sprayer and neutralize the entire fireplace with the ammonia-and-water solution.
Allow the stone to completely dry. Apply two coats of a masonry sealer with a paint brush. Allow two to three days of curing before lighting a fire. These steps will brighten up the stone fireplace.