Well, good luck with that.
clearing out comments from my recent activity space
getting rid of messages in my recent activity space
How do I do that please? (Get rid of unwanted messages/posts/alerts in my Recent Activity Space?) They're a real nuisance.

Click on the tracked activity. When that page opens, look just above to the right of the text entry box. Un-check where it says 'track this thread/topic'
You can see everyone you're tracking on this page
Homepage / Account / Alert & Email settings
You can also turn off other comments and auto tracking from there aswell.
Remember to save changes :)
getting rid of messages in my recent activity space