In its Home and Garden section, The Washington Post recently spoke with Chuck Muehlbauer, the technical director of the Natural Stone Institute, a trade association that offers training and technical advice about the use of stone in building applications, on how homeowners can restore discolored slate and get back to appreciating their original interiors. 

His expert recommendation? STONETECH^Ⓡ Epoxy Grout Haze & Coating Stripper by LATICRETE.