I suspect it's not entirely unlike dealing with scratches from some PO. Something I'm dealing with right now. Begin with a good orbital polisher and some F9. Like Alan points out, though, this means removing the clearcoat -- and suddenly the job becomes a lot more complicated.
If those scratches are from a grizzly, though, you might just want to keep them as a momento! So much cooler to tell people about than some less than wonderful previous owner's misadventures!