Milk jugs not good enough. BWAHAHAHAHAHA!!!
I remember my stepdad having like 5 milk jugs full of used oil in his garage. I swamped my CJ in deep water and had a chocolate milkshake going on. I drained the motor and used his old oil, just to get the water out of the engine. I was thankful for the old oil. Sucked having to buy like 4 oil filters to go through the madness.