Pop the disk into the freezer for a few hours (or a day). It has to be long enough for the components to all get cold. This shrinks the materials and could possibly unstick heads from the platters. I think it has worked two out of four attempts for me. This is a method to get access to the data of which you should extract as soon as possible.

Be cautious of condensation on the cold disk as it could potentially arc circuitry.