This really is pretty simple. All you need is a hammer to remove the nail obviously, your precious piece of wood, and a small scrap piece of 1/4in. plywood. Sorry about the pictures, my camera is broken so i gotta search for pics:D sorry!
Step 2: Extract the Nail or whatever is stuck
Ok now put the the small piece of quarter inch plywood underneath the hammer and pull out the nail like you normally would
Like in the picture down below just put the quarter inch plywood under the hammer
Step 3: Finish!
Woo now you have damage-free wood. Great if you have a project that you can't mess up.