Any ideas how to get them out short of drilling?
Buddies purchase. Nipples are rounded so really no flat portion to get a side box wrench or a nipple wrench on them.
Am looking for ideas. I thought of soaking the nipple portion in boiling water. They had been liberally soaked with wrench eze.

The best approach is to drill them with left hand drill bits. Start with the small diameter bit that just fits inside the nipple. Then go to progressively larger sizes. The nipple will usually come out on the bit before you get to a diameter that cuts the threads in the nipple seat.

They must be really stuck in there. I would not boil the nipple portion. Maybe try a heat gun targeting the nipple and keep putting on some Breakfree " lubricant to soak into the threads. That worked for me on a couple of old muzzle loader nipples that were rusted in place . I would try that 2-3 times before grabbing them with vise grip pliers .
It wouldn't hurt if you could find a container to soak the nipple portion in after heating up the nipples with the heat gun. It takes time to soak into those threads.

I have a set easy outs and the smallest one has extracted nipples for me with out drilling them first.

Well I passed this information on. Thanks gents.
JW