Thanks to Douglas Nelson I got it:
http://www.polaroid.com/service/software/poladsr/poladsr.html <http://www.polaroid.com/service/software/poladsr/poladsr.html>
Oh, wait... my hard drive's full of them.
Never mind.
I used the Poloroid filter on the entire image, then backtracked and painted the dust and scratches effect back in just on the problem areas with the history brush, varying opacity as necessary.
I then finished up with the healing brush.