American Flyer 960/961/963 Passenger cars

[Anonymous]

i just purchased 3 cars from an estate sale. Two of the cars are a lighter shade in colour.
It almost looks like one of the cars is a true silver and the other two are a faded silver.
I tried cleaning them with everything safe to use and still there is the colour difference.
Now, I am wondering if there are two possibilities.
Were two cars from a different paint batch in the AF factory, or did the owner keep two of the cars in the sun light?
Does anybody have other ideas or suggestions as to how to get the other two cars the same colour.
Thanks,
Vincent.