Deleting Old Email Addresses From Cache?

Two of my contacts have changed there email addresses, and I updated it in contacts, however as I begin to type there email in the "To" section I get a list of emails addresses popping up including the ones I deleted from my contacts. I assume they are coming from some kind of cache, but have not found a way to delete those emails that pop up. It's a nice feature, but if the emails are not correct it really does not help.