What is Klean-heat made of? I looked on the jug and it did not say and I looked on-line and I could not find an answer. I am asking because the warning on Klean-Heat warns you not to use it near a furnace because the build up of fumes from Klean-Heat can ingnite. I have a furnace in my kitchen. I thought Klean-heat was a form of parafin. Thanks.