Click on My Account, then Settings, then in the blacklist text box, put every tag you want to blacklist on a different line, like this:
Tag 1
Tag 2
Tag 3
Etc.
It won't immediately take effect, but eventually thumbnails from posts that contain the blacklisted tags will be hidden from normal view. You have to be careful, since when you search for a tag that you have blacklisted, you won't see any results (though you can click a link in the sidebar to make them visable).
Also, it probably would have been better if you kept all of these questions in a single thread.