Originally Posted by cicadashell
if you plan to remove it mechanically, be sure to dose it with a penetrating oil (i use liquid wrench) beforehand - like the night before, to give it time to work.
I was just faced with a stuck bottom bracket (4 yrs of winter salt=bad), and had good luck pouring a bit of motor oil down the seat tube the night before as well- gets all the threads from the inside.
fatbat