Rusty front bumper hardware
 

It seems the ocean air from having my car shipped from Japan to the states destroyed most my hardware and I'm in the process of replacing it. Everything else was easy except the front bumper.
I was able to free all but 3 of my front bumper bolts and they all got stuck at the middle/end of the bolt. However it seems the bolt was welded/built into the bumper and it broke free and the nut and bolt now spin together.

It seems the back end of the bolt is just a quarter sized round end. Which is where I'm wondering if anyone has any tips to free/restore my now hanging front bumper.
I've tried PB blaster/WD40 and evapo-rust. At this point I'm just seeing if anyone has any other bright ideas before I attack the rusty little bastards with a dremel, diamond cutting wheels and curse at it until I get them free.

ofc this had to happen on a Friday....

Can you safely apply heat via a torch?

cut it in half. its an m6 bolt? cut it in half

I'd be very nervous to apply heat there so much stuff nearby for me to destroy. they're right behind the fender well next to oil coolers,cables, headlight bucket and plastic galore.

They are M6,I did finally manage to cut 1 in half. In the process of getting the bolt to stay still I cracked some of my bumper paint right around the seam that meets the fender :(