Good day,
Our small office server was set up to only deliver email locally. I checked the admin messages with a local email client. I will be moving and would like to check the admin messages remotely. As a test, I set up the admin email to forward to my @gmail.com account. However, gmail probably doesn't like the messages because they come from an unregistered domain.
No, that's not true. They are rejected (by wsfo.org's mail server) because they are coming from an IP address (i.e. your WAN IP address) which is listed in a spamhaus.org blacklist. Did you not read this?
Rejected - listed at spamhaus(see
http://spamhaus.org/zen/)
I don't see anything there about "unregistered domain".
Will they eventually be purged automatically?
They have already been purged from the queue, because of the 530 status (permanent rejection). As a result, a bounce message has been generated. It is probably the bounce messages which you see in the queue. If those are also rejected, there will be a new bounce message (a double bounce message) which will be delivered locally.
Or can I purge them with root privileges?
You could, but it's less likely to cause problems if you just wait until the queue clears.