RCP User Manager can do the following for you:

• Remove user accounts that have never been logged into
• Send reminders before removing a user from the list
• Customize the emails that are being send out
• Handle bounce emails. User accounts that trigger a bounce message are automatically deleted on the next run
• Opt-out feature, so user can delete their account with a single click
• Whitelist email accounts that should never be deleted
• Set the maximum number of emails to send out per batch

To be able to use RCP User Manager your hosting provider must allow for cron jobs to be run as a script. The script cannot be triggered via a URL.