I allready started to clean the speedometer and late February, I took care of reassemby it.
To remind you, I had rust inside that I handled with Restom product and some steel wool.

Some marks are left but no more rust. I’ve apply a protection from Restom with a paintbrush et it should not rust again.
I’ve taken care of both and of the front light as well. I still have work for the front light but I’ve reassemblied the speedometers.