Deleting Inactive users

I'm running Elgg 1.7 and i have 307 members, with 815 inactive members showing in my stats.

I don't see a way of deleting these inactive members out.  I looked for some sort of distinguishing field for inactive users in the users_entity table, but found none.  I've read on here where other users have had the same issue, but no clear answer.  ANy help would be greatly appreciated.

My main reason for wanting them gone is because i'm using a group mailer that mails to all of the site members, and i don't want to overload my server with mail if it is indeed trying to email active and inactive members. (vazco group mailer).   Any one with any info on this -- advice greatly appreciated.