Fun job removing particleboard underlayment. I set my skil saw to the depth of teh particleboard and cut it into squares. Then used a pry bar and mallet to pull up each square of board. This made it easier to remove, handle and dispose. One word of warning...DUST. Cutting this stuff will generate a lot of it, so isolate the work area or be prepared to clean. In my case I replaced the particleboard with an ACX plywood and covered with rosin paper as underlayment for wood floors.