With time, even the tiles on a well-constructed fireplace look worn and tired. However, if you like the original tiles, you don't have to replace them with new ones. Old tiles with character add value to your home. Simple cleaning and grouting can restore the appearance of the old fireplace. Afterward, if you still don't like the way the fireplace looks, find a good artist to paint the fireplace to hide the cracks.
Place the end of a chisel against the edge of a loose tile and tap a hammer on the other end to gently remove the tile. Continue to remove all loose tiles.
Remove the adhesive underneath the loose tiles you took out, using the chisel and hammer.
Apply thinset adhesive on the back of the loose tiles with a trowel and press them back into place, twisting them slightly so they stick well to the fireplace.
Remove dirt and debris from the cracks in the tiles, using a small paintbrush.
Mix grout with water in a bucket, following the instructions on the grout packaging. Use sanded grout if the joints between tiles are wider than 1/16 inch or use unsanded grout for narrower joints.
Spread the grout over cracked tiles and joints around newly reinstalled tiles. Use a grout float to push the grout into the joints and the cracks.
Fill a bucket with water and dip a sponge in it. Squeeze the sponge to remove excess water and use it to wipe off excess grout from the surfaces of the fireplace. Rinse the sponge when it is covered with grout and continue until the surface is clean.
Turn the sponge and run the edge along newly grouted joints and cracks to create smooth, even surfaces. Let the grout dry and cure for a few days.
Mix oxygen bleach with warm water in a bucket according to the label directions and pour the solution all over the fireplace. Leave the solution for about 30 minutes.
Pour some of the oxygen bleach solution on a section of the fireplace and use a brush to scrub off any dirt and grime. Repeat until the grout is clean.
Rinse the fireplace with clean water.