Blow it out with a torch. The nut is already spinning and you will have to tack one back on. By the way, what's wrong with an impact? I would have used an impact on those bolts and all bolts that need to be tight and not torqued.
the problem is if your using an impact on a fixed nut you best not be the one taking it back apart, it almost always beats the crap out of them especially if they have been there for 30-40 years
