Used Engine Oil
Used engine oil or waste engine oil is a used lubricant or waste engine oil which come from in any use of the machine.
Used Transformer Oil
Hydraulic oil is different than other lubes. Not only is it a lubricant, it's also the means by which power is transferred through hydraulic.
Only a fraction of the crude could be refined into kerosene, the early refiners were left with quantities of petroleum by-products.
Furnace Oil is one of the cheapest fuels available for industrial use. It is a by-product of petroleum refineries.