With a little care in choosing what phrase to cue on, you should be able to create a Mail rule that will automatically delete these messages before you see them. They will still take up bandwidth and disk space but at least you will not have to spend the time or deal with the annoyance of deleting them.
"All you've got to do is own up to your ignorance honestly, and you'll find people who are eager to fill your head with information" --Walt Disney
