Our waste oil tank is 300 gallons. A few gallons of solvent gets lost in it. In our area waste oil goes for bunker oil. Once ships get out into open water, no one cares what kind of smoke they put out. They are very particular about anti-freeze being in the oil. They take a probe from the bottom on the tank before pumping. Clear water doesn't seem to bother them. We have had some companies in San Antonio that claimed to re-refine used motor oil. But they all came and went. Once they poofed off their government money, they were broke. Kinda like the ethanol plants have done over the past 30 years.