Nothing short of a bit of mussel and grunting with the element spanner is best, if all else fails you could drill it out through the centre then insert a hacksaw blade through the drill hole and cut just enuff of the element to enable you to split it and then get it out through the threads. When you put in anew element is always pays to put a little graphite paste on the element threads to eliminate this kind of a problem happening. Hope this helps.
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