you can try it out on mine... i found a spot on the bumper that i had missed :(

i found autogylms bumber black works great

Where can i get the autogylm ?

Does it just cover it though?

i tried some citrus cleaner...its actually wax remover for skis, but no one ever actually uses it for that, anyways it left a little bit of random splotchiness but took all the wax away, then probably to go over with some tire shine to even it out...
I doubt that shit is good for your paint though so be careful lol