Like all Leaf owners, the plastic trim in front of the windshield on my Leaf was stained and faded. I don't know what they make that out of, but it does not age well and nothing seems to clean it up or keep it nice.
As a part of doing the ceramic coating on my leaf, this thread: https://mynissanleaf.com/viewtopic.php?f=27&t=31058 , I did some work on the hood plastic trim piece (I think it is called the 'hood cover').
I used a dual action polisher with a microfiber finishing pad and first used Meguiars Ultimate Compound for two passes and then three passes with Meguiars Ultimate Polish. It was super easy to do and the result was shocking:
After (this is the bare trim after polishing and wipe down, no water, protectant, wax or sealant of any kind), it looks better and clearer than this picture suggests:
I treated it was a ceramic coat afterwards and it looks even better.