[A/S] Airstream Skin

["Jim Greene" <drgreene@xxxxxxxxxxxxxx>]

I have seen reference on the list to the fact that some of the newer 
(non vintage) coaches do not lend themselves to polishing the exterior 
skin because a different aluminum was used compared to earlier trailers. 
When (which year) did the new skin material change to the "non-polish" 
type?
It presumably would be easier to fix minor scratches and scrapes from 
normal travel and use if the skin can be polished to remove minor 
surface blemishes.  Thanks.

Jim Greene