I thought you might find this post interesting as it’s a little unusual. I had arrived at a client’s house in Boars Hill near Oxford to do a travertine floor and she asked if I could also take a look at her fireplace where one of her dogs had urinated on it. Urine is acidic so if not quickly removed it will start to eat away a sealer and in this case as you can see from the photo below it left a mark. It was quite a small area and as I already had the necessary products to deal with it I said no problem.
Cleaning a Slate Fireplace Hearth
The urine had penetrated the existing protective seal so to get a uniform appearance it was going to be necessary to remove the covering and re-seal. To do this I covered the hearth in Tile Doctor Remove and Go which is a tile and stone friendly product for removing of protective coatings. This was carefully scrubbed into the stone and bit by bit the old wax/seal was removed exposing the bare slate.
Sealing a Slate Fireplace Hearth
The stripped slate was now clean and all trace of previous sealer had been removed but once it had fully dried was left looking washed out. This was easily remedied however by applying a coat of Tile Doctor Stone Oil which brought back the deep black colour. When the Stone Oil had dried I finished the job off by applying a coat of Tile Doctor Ultra Seal which is a natural look sealer that will protect the slate going forward.
Source: Slate Fireplace Hearth Stripped and Sealed in Oxfordshire