I remember an oil that was highly regarded back in my early days of the car repair biz. I think it was Drydene brand, could be wrong but it was touted as having better lube specs because of the refining done the second time around.
That brings up another question. Why was waste oil going for $1 a gallon until the last crude price drop? Makes you wonder where it was going doesn't it? Heck, in the early 80's we used a waste oil drip in the shop wood stove just to get rid of it. That wood sure burned hot. In later years we paid good money to have it hauled away. Everything goes full circle I guess.