"Cool celler"? Pshaw! The MSD sheets state "indefinite stability" for finished motor oil product at any ambient temperature suitable to human tolerance. This is motor oil, not wine. Nor am I at all sure about the simplistic, across the board claim that spent motor oil has reverted back to crude petroleum, either. Petroleum out of the groun is an amalgam of near infinite hydrocarbons laced with sulfer and nitrogen. Spent motor oil is a considerably more defined mixture of hydrocarbons still of sufficiently low molecular weight to pour easily with excess oxidative products. While it can be re-refined, to my mind, it's questionable to equate it with crude petroleum.