I curbed one of my Volk GT-7 rims.
Can anybody recommend a place to clean up the edge of the rim and re-finish the lip.

 

You'll probably end up having a custom body shop do the work if indeed the damage is repairable. It's fairly easy to fix damage with special compounds, or build up a damaged area by tig welding some addition aluminum on if the wheel is then going to be painted. However if the wheel is to stay polished aluminum, that makes things tricky. I do the repair and painting of damaged rims, you can pm me a couple of close of pictures of the damages if you like.