Has anyone else found that the burners of these S. Korean stoves rattle? I don't mean in operation, when they roar lustily, but just when moving them about.... Recently I had to heat and quench one of these burners which was performing poorly. When moving the burner head around I could hear a quite disrinct rattle, as if something was loose inside. But what? carbon particles are too light and any debris might be expected to flow through the tubes when I applied a powerful water hose to flush out the head. I then thought that perhaps part of a sand-core had been left in the top-piece of the burner head during the manufacturing process. These sand- cores form the tubes which run at right-angles across the top of the burner: A shaped "core" made of sand is included in the casting, then "rodded-out" (removed) before core-plugs are brazed in to close the two side access holes. I drilled out one of these core plugs to investigate: The top tubes were clear, but I could just see the top of an obstruction in the burner "up-tube". With a lot of patience I was able to extract the offending piece via the base of the burner: It was a spiral of brass strip, obviously factory-made and part of the burner design. There is a matching one in the other "up-tube".I guess they are intended to improve the paraffin vaporisation process, but I have never seen them in any other burner design. I have re-inserted the spiral and will re-make the core-plug seal when I get around to it. So, there you have it. If you ever shake a Shinabro burner, and it rattles....you will know why. Best Regards, Kerophile.