Last year I ran a script to do just this. It didn't get everything, but I eventually gave up. I recently tried Social Book Post Manager to accomplish the same thing.

While it did a better job, despite my activity feed being clear, I'm still seeing a lot of posts.

The rub is that I can delete posts that show up from 2008, but that same post will show up on refresh.

Looks like I'm moving to Europe for a day in a few months.