I didn't have much luck searching Google on tips to cleaning the license plate from exhaust carbon. Granted....99% of the cars on the road don't have a centered exhaust output.
Soaked it in water for an hour while I washed the car, dishwasher detergent (I used Joy), and a steel wool pad. See for yourself!
And yes it's a lot of carbon - it burns oil and I hadn't cleaned it in a very long time.
Before and After
