[Dovecot] Maildir Index Question

We have several hundred mailboxes that have thousands of files in them (spam boxes)

We currently run a find command and remove the files that are over 7 days old but still have boxes with upto 60k messages in them. I know that dovecot will update the index files for each mailbox when the boxes is accessed by an IMAP client(Webmail using Squirrel)but that can take quite a while to index.

What I would like to do is via a cron job after the old file remove is to force dovecot to reindex these boxes. That way when the users login to the webmail interface it is quicker.

Does anyone know if a script is available to do this?

Thanks

Ron Culler