If you aren't planning to use it again or sell it you could just open up the plug the on the bottom and let the data drain out. It's like an oil change....takes a couple of hours for it to drain completely.
there's a metal foil cover on the drain plug on top of the drive. rip that off and unscrew the drain plug. Turn the drive upside down and leave it for a while. I'd do this outside, depending on the information you have on the disk it can be quite smelly. If you want to make sure that absolutely all of the data is gone, put it in an over for about 10minutes (200 degrees) after you drained it. The heat will evaporate any remaining data residue.
JUST REMEMBER THE DRIVE WILL NOT BE USABLE AFTER YOU DO THIS!
I've heard of some people that re-injected data into drives after they were emptied, but that's really hard to do and you need to find a good source of clean data...in fact, I think the EPA has banned the use of canned data in the US, so that's out.
If these seems to risky, then just do what everyone said, reinstall and wipe.