Bewere loosly fitting crank extractor when dealing with aluminium cranks.
It happens that when it is very easy to put extractor in you may end up with ripping the thread out.It happened to me 2x.
Ooops…
I’ve had the opposite problem; a tightly fitting crank extractor that does what it is supposed to but then cannot be removed from the crank!
Does anyone make a crank-extractor-extractor? And if they do, how do I extract that?
Phil
Sooner or later you use a really, really big hammer or a really, really big spanner, or ideally a combination of both.
I might have had the problem with a loose fitting crank extractor, but I think the problem was more due to a combination of cheesecranks™ and me intermittently being a muppet.
John
Are you sure it was the fact that it was loose? Because i know if you dont screw it in ALL THE WAY then you run the risk of yanking out oyur threds.
All the more reason to use anti-seize on anything that’s threaded and you want to remove. That’s your extractor-extractor… and you can extract that with a rag! 
Not screwing enough…?
The only reason why I hava put my remark in was ,because in those two occasions I have used very good quality extractor and…I HAVE SCREWED IT IN WELL.
The mantioned by you mistake I have done already in the past. 