Didn't take long, just washed the wheel then rubbed down with some fairly rough wet and dry paper (had it lying around already so don't know grade) then used finer paper till the area was reasonably smooth. Then got out my old favourite the Solvol Autosol metal polish, as it is an abrasive paste, keep it off the painted bits and rub down the now smooth damaged polished bits till you can't feel any damage. This bit is best done over a few times till looks ok to the eye, then polish off with a buffing cloth and add some clear lacquer to protect, (I used a SEAT stick) When all dry, wax the wheel with a wheel wax like Angel Wax or similar and done, not perfect but hardly visible.