Possible Clues:

• Unrefined petroleum
• Cold, sharp local Texas tea needs to be refined
• Petroleum, cloudier if unrefined
• Could be cloudier but still needs to be refined
• Well stuff
• Black gold
• Primitive picture that has boring producers?
• Wind up accepting rude and unrefined material
• Unrefined painting that's well-produced?
• Potential source of energy, wind — what's offensive in that?