I'm working on my first guitar.  I was a little overly ambitious and glued the heel block to the neck.  After the glue was really dry, I realized that I had forgotten to plane the headstock.  Naturally, when I planed it, the line for the intersection of the neck and headstock moved about 1/4".  That meant that the the heel block was not in the right spot.  I know it is only 1/4" off but I want it perfect.  The problem is that I can't get the glue to loosen up.  I'm heating the joint in an oven on about 200 degrees farenheit and it won't budge.  I'm worried about cooking the wood!  Is there a better, easier, smarter way to break the bond?  I thought about putting some water on it but I'm afraid it will stain the wood.

Thanks