Skirting boards are immensely recyclable but care must be taken when levering the wood away from the wall.
Score a line using a sharp blade between the top of the skirting and the plaster. You may need to repeat this process several times cutting through paint and caulk. This will hopefully limit paint and plaster being pulled away from the wall when the skirting is removed. The skirting board may have been fixed to the wall by nail, screw or glue. One cannot always tell by simply looking at the board.
Start with external corners or where the skirting meets the door architrave/door frame. You will need to use a wrecking bar to loosen and lever the board away from the wall. Insert the sharp end of the wrecking bar behind the skirting. You may need to tap the bar lightly with a hammer. Place a small off-cut of wood behind the bar and against the wall – this should lessen the damage caused to to the plaster – and gently lever/pull that section of the skirting away from the wall. It is likely you will cause some inevitable small damage to the plaster. Do not attempt to pull the whole board from the wall as it may snap. As you slowly lever the board away from the wall insert wooden wedges between wood and plaster every 2ft or so.
Move along the whole section of skirting board repeating this process. You may find the skirting is stubbornly still attached by its fixings, i.e. nail or screw. If the skirting has been fixed by screw gently knock around the screw loosening the paint and filler which conceals the screw head. Now remove the screw with a screw driver. If this is not possible the screw will need to be cut with a junior hacksaw or a chisel. Follow the same steps if the skirting has been fixed with nails but when pulling out the nail remove it from the back of the board to limit damage to the face side of the skirting board.