I was atleast one of the guys saying to soak these in K-1, but that only works if corrosion is what is seizing metal to metal. If these are installed overly tight for some reason, and I have never seen one installed that tight, no lube, or penatrant is going to deal with crushed and mashed threads.. If a nipple is cross threaded no lube will make getting it out easy, or fix anything.
Nipples should be installed just good and snug. There is no reason to install them until they snap off and then back it out 3/4 of turn.
I am an x foreign cars tech, and so have removed hundreds of broken bolts and broken exhaust studs. They all share ont thing, that is none of them are much fun.
Long before i used an EZ out, I would use a impact driver, and padd everything.
EZ oputs are dead last in the order and these tend to swell parts even tighter.
Of course with cars you can use a lot of heat with a act oxy torch, but I also do motoe bikes with chrome, and heat there will ruin chrome.
If you use the right tool the first time you won't bugger parts. It is tools like pliers that ruin things.
On guns the worst tool is a std screw driver, because gun screws are nothing like std wood screws.