Slate is an ideal material for a fireplace hearth because it is able to withstand very high temperatures. It also adds beauty to the room, so you want to keep it clean. Fortunately, it is easy to keep your slate hearth clean and shiny.
Before cleaning the hearth, test clean a spot that is hard to see. You can make the cleaner by mixing a couple of drops of a mild detergent like Ivory Soap in 2 cups of warm water. Soak a rag in the solution and wipe the surface of the hearth clean. Allow to dry overnight. Then apply teak oil—available at any hardware store—to the entire surface. Afterward, wash with Spic and Span, which will break down the dirt and not harm the slate.
Thoroughly rinse the hearth to get all the cleaner off and let dry. Finally, apply furniture polish and rub in to a deep shine.
It is a good idea to clean the hearth regularly every 3 months, even if it doesn’t appear dirty, to avoid having to tackle a major cleaning job. If you live near a quarry or stone manufacturer, you can get slate cleaning oil, but the teak oil works just as well.