Zinc oil supplement

The tool and die shop I worked for(I’m retired) recycled way oil in a purpose built commercially sold recycler. All it was is a tank that heats the oil to rid it of moisture and ran through a fine micron filter suspended at the top of the tank which aireates it as it sprays to the bottom of the tank.

The problem is that it is mixed with minor amounts of coolant, cutting fluids and hydraulic oil which after time jellies and creates sludge. Also when the container of the tank farm had recycled oil in it and container was just about empty, you could see foreign material in the oil.

Buy recycled Motor oil? Not in my car.