A couple of guys filled in some of the details above. I always tape the wood at the pad and cut the the pad close to the wood. Belt sand the remaining pad off of the stock, which also squares it up for new pad installation. I always buy grind to fit pads and use one of my jigs from Brownells or Midway to grind it properly. It's a very easy, but somewhat lengthy process. I found it's the best way to ensure a good, clean installation. Just take your time and watch the angles.
