I had a steel seatpost stuck in a steel Gary Fisher frame. Heated it up with a plumber's torch- not enough to burn the paint, just to get it nicely warmed. Soaked it in PB Blaster, clamped it in a bench vise, and twisted.
The seatpost twisted in half like licorice. Ended up cutting it out with a hammer & chisel in thumbnail size pieces. About 2" is still in the frame, rattling up and down. Still won't come out.
But the frame is usable and there was no damage to the seat tube. An artist with the old H&C am I.
And that's a good score. Nice bike.