I know that the hot wire in them is platnium or at least platnium coated. Just like the O2 sensors.
I have a large supply of these for I run a auto scrap facility. But just haven't taken the time to deal with them.
Also have taken apart many of the ecm's and have discovered a good amount of gold as well.
Maybe I should see if lazer steve could put together a vid on this pm scrap.