1. Unmount SD card, then remove it.
2. Put it in a PC, set to see hidden files, delete everything.
3. On the droid, Settings > Privacy > Factory Data Reset.
4. Yank the battery out and have a really cold beer.
5. Power on and confirm that it knows nothing.
6. Reinsert and mount the SD card.
7. Launch gmail app to make sure it has no idea who you are.
That