>>>Magnesium is highly reactive. If you see an old air-cooled VW on the side of the road (magnesium block) with an engine fire - don't try to put it out with water!!! <<<

EEK! Don't tell me these things! My son is into old VW's (especially buses). It's bad enough that they have no seatbelts and nothing between the front passengers and any front end crashes. Fortunately the bus spends more time sitting in the driveway waiting for repair . . . er, restoration.