SLCHOE
ASE Master Certified + (L1)
Yeah, get yourself an O2 sensor socket and also spray a bit of penetrating oil a few times a day on the O2 sensor where is screws into the piping for a few days before you do the work!
Or hit them with a propane torch around the bung till they glow and then hit them with the PB after they cool a little if they're really stubborn. The heat expands the threads in the bung away from the sensor threads breaking away the corrosion. The PB seeps into the already broken free threads and lubes them up.