Hi David,
Yes,
omtidyallu is the utility you need to run. You can use wildcarded sender and subject strings to make the selection. Just using just
omtidyu without actually deleting any items will allow you to test that the filter criteria are correct.
For example:
omtidyu -B -u <user> -Ti -a 0 -m spammer@acme.com -t *pills* -R
will list the messages in the user's Inbox that were sent by
spammer@acme.com and contain "pills" in the subject.
When you are happy with the filter you can apply it to everyone and delete the items:
omtidyallu -Ti -a 0 -m spammer@acme.com -t *pills* -d -k
(The items will not be moved to the Deleted Items folder as the -k option is specified, but they will be moved to Recovery Folder.)
Cheers - Richard