Replace the locks, had to do that on my sons car.

I had the same problem when I bought the car (91) a few years ago. The key
was worn so badly it was difficult to make it work in the locks. I found a
key cutter at a small local hardware that was willing to spend some time, as
use a few blanks to overcut the key, and then keep shaving it until it
worked just right. Basically he shimmed the key in the cutter by using some
paper to cause the new key to be cut slightly wider than the worn original.
He then just kept shaving it a little more, trying the key in the door lock
after each shave until it was perfect.

It took a bit of time, and a few blanks, but much cheaper and faster than
replacing all the locks and getting new keys.

Actually, what I did was to remove the driver's door Lock and freed it up
(it was frozen).  I still couldn't OPEN it, but it was better.

I took it and the original key to the locksmith.  There was a number on the
key and they cut a key to the ORIGINAL FACTORY Specs and now ALL the locks
work perfectly.

NOTE:  IF there is a number on you key, have a locksmith cut a NEW one, NOT
a copy, and they'll work like New.

Mike