ORIGINAL: noterman
Try finding a socket slightly larger than the blind nut, insert a screw and washer through drive side of the socket and into the stuck blind nut from the blind nut side of the firewall, then tighten the screw to pull out the stuck blind nut into the socket. Basicly using the socket/screw combo as a a ''puller'' to free the blind nut. hope this helps...
While the heat is a great idea, this puller idea with the socket sure is uber clever! Gotta remember them both for the future! Jon