[AXMonster]

O2 sensors can be brought back to life by sitting the tip in lemon juice.

I know it seems wired, but it works! How long it works for I don't know, but heating with a gas torch, then sticking in lemon juice overnight would probably be a good method.

I cleaned a regular O2 sensor on my Supra and although it looked clean on the outside casing, the amount of crud that came out in the lemon juice was amazing.