We had a job coming one night of a customer that accidentally broke off the tip of the key to her 95 Geo Metro. Although there is not a specific procedure that most locksmith technicians do to take care of the problem, this is what I came up with:
First what I did was to use a blank key and broke the tip of approximately as far back
as hers had broken off(if the customer has the remainder of their key, you can
use it for this next part) and inserted it into the ignition. This gets the
tumblers out of the way.
Next, I threaded a spiral extractor down each side of
the key, using the millings on the key to guide the extractors.
Then I clamped
the key and the extractors together with vice grips, placed as closely to the
face of the ignition as I can get them. The key and the extractors should be virtually "welded" together and by the vice-grips. Once that was done, I used a screwdriver handle between
the housing and vice grips in leveraged the key and extractors out of the ignition. The tip of the broken key came right along with them.
If you need similar service around Portland area, don't hesitate to call NorthWest Locksmith.