My neighbour is a retired civil engineer. He has an oxygen sensor that is faulty. But he did some internet research and found out that oxygen sensors usually fail because the sensor tip gets dirty...he went on to list a bunch of possible contaminates such as lead (from gas), oil ash, silicon, water... The sensor tip is encased and not accessible but he thinks he can clean the sensor tip but submerging it in a solvent: fuel injection fluid. He thinks that's the safest solvent. Question: Is he crazy?