Originally Posted by RoyBoy:
Mothers mag wheel polish, Simichrome, or a rag buffing wheel.
Don't try to clean it chemically as some of those chemicals are too harsh and will etch the aluminum, like one that came from eBay a few years back.
The decals are available, but I don't remember where. American Flyer vendors would know.
I'll second Simichrome - I've cleaned up a Flyer Zephyr and about 2 dozen AMT/KMT aluminum passenger cars with it and it does an excellent job.
I used to buy Flyer prewar parts from Ron Leventon - you might try him for the decals:
http://www.americanflyerparts.com/
Doug Peck would be another good source to ask: