I bought a replacement o2 sensor for my 89.  But I can't get the old
one off - it's rusted on pretty good.  Tried using rust solvents with
no success.  So my next step may be to saw through the sensor so the
remaining stub is short enough for a 22mm socket on a breaker bar.
The deepest socket I found is too short to fit over the intact unit.

Thing is, I don't know what is inside the o2 sensor that makes it able
to sense oxygen levels and I'm worried it might be some kind of cancer
causing substance that I should not be creating clouds of.  Anyone
know the answer ?  If it means saving my health, I'll just buy another
catalytic converter.