Never and I mean never use even a light abrasive anything on a finish that you don't what scratches on.
I use very warm water (not hot), a smooth washcloth or sponge (non-abrasive) with Armor All Car Wash it comes right off without much effort and leaves no scratches to the finish.
About the only thing I could suggest is Walbernize super seal. It can take light scratching off the coating. I have seen it remove/fill some very light surface marks. Other than that, if Walbernize super seal won't help reduce the visible scratches, they'll be there as a permanent reminder never to use an abrasive anything on your exterior finishes.
Computers manufactured by companies such as IBM, Compaq and millions of others are by far the most popular with about 70 million machines in use worldwide. Macintosh fans note that cockroaches are far more numerous than humans and that numbers alone do not denote a higher life form. -NY Times 11/91