I had a forum that I installed a while back and then removed it a while after that. In that time, it seems the forum received all kinds of spam sign ups and posts that I didn't even know about. In looking at my stats, I'm seeing a ton of 404 errors and most of them are related to forum pages that don't exist. Is there an easy way in Google webmaster tools that I can tell google to remove everything under the /forum folder of my site from its index?