Lay 3-foot wide strips of cardboard along each edge of the hearth to protect the flooring. Tape it to the floor with low tack painter's tape to keep it in place.
Put on a mask and goggles, a long sleeve shirt and heavy-weight jeans to protect yourself from dust and debris.
Attach the chisel bit to the demolition hammer according to manufacturer's instructions. Demolition hammers are available for rent at many hardware stores.
Turn the demolition hammer on and place the chisel tip about six inches from the edge of the hearth. Work the chisel tip toward the front or side of the hearth at a 45 degree angle. Chip off a small section of the hearth.
Move the tip of the demolition hammer over a few inches and chip off another piece of the masonry. Continue working in this way until you have removed all of the masonry materials.
Dispose of the large pieces of material. Sweep and vacuum the small pieces of debris and dust.