IMAPFilter (a mail filtering utility)

IMAPFilter connects to remote mail servers using the Internet
Message Access Protocol (IMAP), sends searching queries to the
server and processes mailboxes based on the results. It can be used
to delete, copy, move, flag, etc. messages residing in mailboxes at
the same or different mail servers. The 4rev1 and 4 versions of the
IMAP protocol are supported.

This requires Lua available at Slackbuilds.org.