Can Additives Settle Out Of GL-5?

[cci]

MasterPro GL-5 80w-90, sealed container, been sitting at least 15 years. The oil was light honey colored with little or no odor until I got close to the bottom of the bottle, at which point the fluid coming out was black.

Is it possible that the additives settled out?

Should I drain this out and replace it?

 

[MolaKule]

Warm it up, shake vigorously, and put it in your diffy.

 

[cci]

Warm it up, shake vigorously, and put it in your diffy.

Thank you, sir!