How do I Delete email Addresses from Outlook Express?

I have an ever increasing stockpile of incorrect or disused email contacts in Outlook that come up as suggestions every time I go to send mail, every mistake I have made in the past (extra full stop, one missing etc.) keeps coming back to haunt me. I have tried everything I can think of to get rid of the things, and it's obvious that I can't think of enough, what is the probably straightforward trick that i'm missing?