10 Steps to One Piece Crank and Bottom Bracket Removal (also applies to cottered cranks)
1. Wrench, grunt, push, pull, curse, yell, scrape knuckles....
2. Apply whatever penetrating oil is handy
3. Get a drink, eat a sandwich, go to the bathroom, work on the rusted on headset...
3. Repeate steps 1 through 3 until it budges.
4. Unscrew the rest of way trying not to dump the 6 million loose ball bearing everywhere.
5. Sneeze, which causes the 6 million balls to fan out over a 153 mile radius.
6. Waste 4 hours trying to locate scattered ball bearings.
7. Swear to not care next time, and replace the loose bearings with caged ones. Or just get a bucket to catch the things.
8. Remove the crank and sprocket.
9. Unscrew everything else that's on the crank.
10. Get another drink, eat another sandwich, go the bathroom again, get back on that headset...
If you have a cartridge bottom bracket I'm lost but can assure that there's some tool that makes it easy.