A method of treating a surface to remove unwanted material therefrom, including providing a foamed glass article formed from a starting mixture including glass, a carbonate foaming agent, and a devitrification agent selected from the group potassium phosphate, potassium phosphate tribasic, sodium phosphate and combinations thereof, and contacting the surface with the foamed glass article while providing relative movement between the surface and the article. The crystal silica content of the foamed glass body is less than 1 weight percent. The surface is treated by sanding, rubbing, scraping, degreasing, polishing, cleaning, smoothing, depilling, grooming, stripping, degumming, and combinations thereof. The surface is selected from the group comprising wood, metal, plastic, fiberglass, porcelain, glass, enameled surfaces, ceramic, concrete, or tile, and belongs to a member of the group comprising pools, spas, griddles, grills, fryers, bottles, glassware, cement pieces, marble, granite, monuments, skin, animal hides, textiles, garments.