Prep the area and wear safety gear. Dropcloths should be placed underneath the mantel to help catch the debris that falls. You can also use a garbage can right there to help catch the tile pieces to make cleanup easier. Put on gloves to protect your hands from sharp tile edges, and safety glasses to protect your eyes.
Break the tiles. Ceramic and stone tiles will need to be broken first for easy removal. Use a hammer, and strike in the center of one tile. Pull the pieces away by hand, or chip them away with a chisel. Continue until all the pieces of tile have been removed.
Apply adhesive remover. Use mineral spirits or a commercial adhesive remover. Brush it on the mantel with a paintbrush, and let it set for five to 10 minutes.
Scrape away the adhesive. Use a plastic putty knife so that you will not create gouges in a wooden mantel. Begin scraping away the adhesive in an upward motion. You may need to apply additional adhesive remover to stubborn spots. The mantel will now be ready for refinishing.