I would try boiling it in water. This may soften up the congealed grease/gunk and might even loosen up the retaining pin. Don't let it sit on the bottom of the pan, suspend it on a bottlecap or something with sharp edges (so it won't transmit too much heat). Make sure it doesn't 'travel' in the heat currents (maybe lay something on top of it).
$.02...
FWIW, my 1900AE retaining pin was loose enough to push it out with a paperclip. You might get lucky...Do you feel lucky???