Red pigment takes in more high energy particles from UV rays and breaks down quicker. That's the scientific explanation. This is especially a problem with organic pigments which were the prevalent available until the mid 1950s. Even then man-made pigments are still susceptible if not protected by clear coats that have UV rejection compounds.

BTW, early Pennzoil had green bells. I had a great sign a couple of years ago that dated to around 1919-1920 with the green bell.



Collecting anything keeps you young at heart!