I want to replace the broken pane in a kitchen door and I am having difficulties at the first hurdle. Round the edge of the glass is something like a picture frame (actually two, it's identical on the other side) with 45 degree angles on all four corners. Each of the four sides is held down by three nails which have been driven into the wood and covered with filler. My first thought was to lever the wood inwards and pop out the nails, but this won't work because each side is held by the sides at each end. It looks like the only way I can get at the glass is to dig down where the nails are and pull all twelve nails out with pliers or something. But this means doing violence to the wood and I'm not even sure it will work. Advice appreciated.