IPs are added to the Truncate list automatically when all recorded events for IP address indicate the message content was spam, scam, virus, or other malware.
There is no way for manual additions. Also IPs are removed from this list automatically, there is no way for manual removal.
When no further events for the IP are recorded, the confidence figure will eventually drop to a point where the IP is no longer listed. In most cases this happens within a day or two. However, if the event was severe and a large number of "bad" messages were detected then it may take a week or more for an IP to be "forgotten".
Is the information on our site wrong or incomplete? You don't want us to monitor your blacklist? Or do you operate a similar blacklist? We would like to hear from you!
We keep some statistics on blacklists. Below is the graph for truncate.gbudb.net. We test blacklists by asking them to respond to known IP's that are blacklisted and known IP's that can't be blacklisted. Not every blacklist has such IP's, we test them with what is possible. We keep if we get any response or error messages and the response duration. Lower response times are better. These statistics may be useful for email server administrators to pick which blacklist to use.