My recent collection purchase included this mickey, CD 257, of which there are straw color examples. Color was darker than other examples I have seen, but I thought I would figure it out later. After talking to other collectors who specialize in mickeys, Hemingray glass and insulator color alteration, it appears this one was irradiated and then the color was backed off partially with solar exposure.
Here is what it should look like with just cobalt radiation-- a burnt amber color [id=501157293].
Enough solar exposure would revert it back to its original color or perhaps a light exposure to cobalt radiation would achieve the gingerale color.
I plan on sticking this Mickey out in the sun to see if the color is stable. Stay tune for future photos.
Less than 2 months in the sun, the color of this mickey reverted to a clear color.