Sometime back some blue 58 Aarons turned up and sold for high dollars as missing color variants, but some of our printing slouths. Ben and Steve I think, demonstrated that blue turns to green after a lot of sun or light exposure.I think Ben posted results of some experiments he ran.
Here are my Mays and Aaron. Fortunately I got my Aaron after the market imploded on them. The amount of blue varies depending on exposure. Some Aarons are much bluer than mine.
You can also see yellow goes white
