Are you wanting to preserve its current state (with some shine) or try and recondition it?
If you want to add shine as-is, you might consider something like
Poppies. These are before/after on a friend's truck.
As far as the gold leaf, I would probably clean it carefully with carwash soap, but avoid any kind of heavy scrubbing or buffing on it. Just go up to the edge around it.
