Clay pots have so many uses - I really like this one! Think the candles RWM made using the mason jar filled with shortening would work well with this. I am also reminded of using two clay pots and some sand & water to make a cooler to store food in.
Update: Used the heater last night and this morning. It does heat up but I'm not getting the radiating heat I'd hoped. Still tweaking the system.
WARNING~ I considered my Crisco candles, but DH's research shows the smoke point to be 350 degrees F and the flash point is just over 500 degrees F. Some people estimate the inner clay pot could reach as high as 550 degrees F. I would stick with regular wax votive candles or tea lights!
I had a chance to experience one of these heaters last week. A friend brought their's over to demo it and I can tell you it works! Nice and toasty ~ the clay pot was warm to the touch at first and gradually got hotter - the bolt on top was quite hot but nothing a pot holder couldn't handle if you had to move it to blow out the candles etc. VERY safe! We just sat it up on my coffee table and it did it's job :)