Well, I picked up a SBZ from Q a while back, and it had a big chunk or plastic taken out of it 
http://img526.imageshack.us/img526/4572/pictureface008.jpg
You can see it haha. THen I filled it up with super glue, and sanded it down. It grinds like when it was new now. Still looks crappy though haha.
Super glued:
http://desmond.yfrog.com/Himg16/scaled.php?tn=0&server=16&filename=pictyaface013.jpg&xsize=640&ysize=640
Sanded Down:
