Just for kicks and giggles I set a jar of my home heating oil out last night to see how it reacted in sub zero temperatures.
I expected it to at least look cloudy this afternoon at -3 but it doesn't at least to my untrained eye.
It's #2 home heating oil I bought in the summer and can't imagine they would have treated it. They usually ask if it's going in an above ground tank, which it's not.
I was just surprised at it's clarity at that temperature. IDK