If you're salvaging old ceramic tile, there may be dried thinset mortar still adhered to the tiles. Thin set mortar is a type of Portland cement, and therefore will be extremely hard and brittle when removed.
Solvent and cleaning supplies will not remove the thinset from the tiles, so you must grind the thinset off. The key is getting the thinset down to the surface of the tile so that the tile is smooth for reinstallation elsewhere.
Things You'll Need
Turn the angle grinder on at the lowest speed setting and hold the pad against the ceramic tiles. Begin moving the grinder in small circles over the surface of the tile. Do not hold the grinder in one place, as this can cause damage to the tile.
Gradually increase the speed of the angle grinder until you find the speed that effectively removes the thinset mortar from the tile. Starting the grinder at too high a speed could result in damage to the tile, since the grinder may eat into the thinset and then into the tile too quickly.
Slow the grinder down again when you approach the body of the tile to remove the last of the thinset without chipping or scratching the body of the tile.
Rinse the tiles in water to remove the thinset mortar dust.