Maybe you could try one of those air-sparkplug cleaners with sand in it, effectively sandblasting it. My father's got one of those - pretty handy. If you don't have access to one you could ship the sensor to me and I'd put it in there for you. There's a nice junkyard here, but not many volvos :-/ Maybe Christ can hook you up - I think he's got 2 yards near him.
As a side not we passed a sizable volvo-only yard on the green grand prix economy run, but it seemed to be only older models.
__________________
|