Fuel for a paraffin/kerosene inverter heater is sold typically in 20L containers (in Europe). They all claim to be highly filtered to remove odour, and burn cleaner. Customers are also given the opportunity to pay more for different brands, but they all seem to meet the same standards. The heater instructions indicate that this high-grade paraffin should be used, and not heating oil. Further, I note that user reports do indicate carbon build up on the flame rod and gasifier, when heating oil is used. Whereas, my heater has only used high-grade paraffin, and there is zero carbon build up. I'm wondering... what is the science behind this? Is filtration just a marketing term, when really the high-grade paraffin is simply refined differently. ... and is it then burning at a higher temperature (than standard heating oil), thereby ensuring that less carbon is deposited. Is this fuel the Naphtha, that is shown on the classic refining charts?