So my Dad had this thing out in the sideshed for a number of years. I think it is a Century, not really sure. But I've plugged it in a couple times and let it go but the lava won't budge. The lava looks way clumpy and messed up. My Dad said that he tried to put a different kind of oil in it and I think that messed it up. Not sure, but I want to fix it and add it to my collection. I'm including some pics of what it looks like. Please help!!