Is there a way I can wipe my hard drive when my MacBook wont turn on?

Hi,

My MacBook sadly stopped working about 6months ago when I spilt water on it...it doesn't detect that there is a charger in it so won't turn on as the battery is drained.

Anyway, I'm hoping to sell it on eBay to contribute to buying a replacement. Obviously I want to make sure all my personal details/photos etc are wiped from it before I sell it but I'm not sure how to do this since I can't actually turn the machine on!

Any help would be hugely appreciated, thanks in advance.

Fliss