I had a case where one cup was rusted frozen on the shell. Sheldon's (usually successful) method wouldn't budge it. After squirting a liberal amount of penetrating oil into the area surounding the cup, I stuck the nozzle of a small portable torch into the shell and hit the cup with a good ten second blast of heat. The penetrant started popping as it evaporated, and I had a little fire going on inside when I pulled out the torch. Then I did likewise on the outside face of the cup, carefully and not long enough to do any damage to the paint on the shell. Whether the heat allowed the oil to further penetrate the threads, or the cup tweaked, or what I'm not sure, but after it cooled down, the cup screwed out with relatively little effort. I realize there is potential for damage, but I just had to get that sucker off of there.
Dennis Young Small canister torches are useful in Hotaka, Japan
> I can vouch for the nut and bolt method on Sheldon's page.
> Works great, might scare you when that cup comes loose with a crack!
> I think I had to do that on my "Raleigh spec" bottom brackets.