Green hue to old Valvoline 20w50: normal or abnormal?

[FCD]

Some oils are or were dyed. However oils using a significant brightstock content or certain other base oils with a high aromatic content can give off a chemiluminescent hue which, when combined with the amber colour of the oil appears greenish. If you have a UV torch shine it on the oil and see if it intensifies.

This!
Many conventional oils i've used have that kind of slight greenish hue.

 

[TheLawnRanger]

Valvoline green with envy of other brands?