[BRENT in 10-uh-C]

The first order is to 'de-chrome' it which is typically done by the plater in a reverse method of plating. Once the panel is stripped to bare metal (-or brass), you can begin the repairs and sanding. Typically I use 400 and then 600 on headlight shells, but I need to caution you that a small buffer with a narrow buff will make the panel wavy. You need a strong enough motor to spin a 2" wide buff. My buffer is 7 1/2 horsepower with a 1" arbor.