Possible Clues:

• Ancient tall Greek/Roman jar
• Sounds as if I'm all for a jar of this
• Old jar containing some camphor and other oils
• Two-handled liquid container
• Greek storage jar
• Oh, a 15 across is enough to give one quite a jar
• Oh, what's in a ramp to give one such a jar?
• Orally support a vessel
• A measure of speed, or a classic jar?
• Enough of a jar to make a ram hop