Remove the stiffening back from a razor saw, not to difficult, use a small punch to flatten out the dimples holding the stiffner on. You can the use this rather flexable saw blade to saw along the edges of the glue joint and remove the old structure. You can also sometimes use an unmounted hacksaw blade to do the same thing. If all else fails, you may have to fall back to the Dremel solution and replace any damaged area with new wood.