Source: The Great Interpretation of Dreams (Ibn Sirin)
Oil that has changed color or smell (murky) in a dream indicates worry, illness, unlawful money, or knowledge that is not benefited from.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
Murky oil indicates breaking a covenant or betraying a trust.
Source: Signs in the Science of Expressions (Ibn Shaheen)
Altered oil is interpreted as worry and illness.