Here's a short clip I had posted in the forum a while back about the topic of dumping stuff into the tank. I found this online when someone mentioned putting ATF oil in with a tank of diesel.
Kerosene is added to diesel fuel by some suppliers, though in small quantitites. Kerosene has virtually no lubrication qualities--adding more (and an essientially unknown amount, since you don't know if or how much has already been added by the supplier!) is a sure way to cut the life of your injector pump. Kerosene is routinely added to home heating oil, in large quantities. The furnace doesn't know, or care. The furnace oil pump does not have the same clearances (they are more crude, greater clearances, lower pressure...) and the kerosene won't hurt them. Most will (and often do) run on straight kerosene--here in NH, if the oil tank is outside, the mix will be either 50/50 or straight kerosene. Kerosene doesn't have the same heat values either, you won't get the same amount of power from a gallon of kerosene as from heating oil, or diesel fuel.
