Related Clues:
- Contents of many a barrel
- What the 'O' in OPEC does not stand for, surprisingly
- Something well-kept?
- Big Alaska resource
- Car engine necessity
- Grease caused some soiling
- "Black gold"
- Subject of a 1973 crisis
- Fish __
- Thing to check on a car
- Cause of some skin problems
- __ well
- Makeup of a slick
- Classic pre-dinner bread dip
- Emulsion component, often