I just came across this post. I know it's been here longer than I have

but I thought the picture was kind of a neat project so I thought I'd see what could be done with it.
All I did was do a copy & move cleanup to the background (see tutorials). I saved my selection and repeated it about 5-10 times and then added some texture. Then, I ran the decrack action. After that I ran the Smart Duster action.
Last, I did a snapshot and did dust & scratches with the history brush and a little tiny bit of cloning.
This is a pretty rough idea of how it might look, but I think with a little more time it might actually look ok...