I use the above method and set it up to record. Later on, I sort through all of the recordings using Trunking Recorder. Whenever I find stuff I don't want to hear, I add the TG's to the playlist and mute them. For the other stuff, I listen for a while and figure out what it is.
I've used this method to ID several new, updated, or rarely used TG's and get them added into the RR database.