I haven't really tried. I don't have the problem of the OP, of scraped content outranking my original content.
Google's new rel=author photo id thing may help?
It may help Google sort out original author?
Some have said they've had success with something as simple as making sure they have a claim of Copyright on the page. Apparently some scrapers will honor a copyright notice, believe it or not. Make sure the copyright notice is in the same source (html) file as your primary content.
But I'm sure in most cases it's much more difficult to actually eliminate the scraped content.