Recycled oil

I worked in a GM dealership many moons ago. We recycled our own oil, a very simple free process. Didja ever see oil that has been sitting in a 50 gal drum undisturbed for at least a year, maybe more, I kinda forgot. Anyway it looks like brand new oil.There were about 3 drums setting there. It was labeled "used car oil"....and was used only for that. We worked out of the oldest drum. In those days, many of us employees would buy it for .25 a quart.
Point being........?????:)