Got this off the Jag Forum.

SECRETS TO TROUBLE-FREE KEYED LOCKS

Agreed, frozen locks are no fun. You must do whatever is necessary
to free the lock mechanism. However, once the lock is operating
correctly, you CANNOT leave any sticky, gummy liquid residue in the
lock. It WILL lock up again. So how do you do it ?

1) Get the lock ''free'' and operating smoothly and correctly by
whatever means.

2) ''WASH'' the lock COMPLETELY (including total submersion) in a
great cleaning solvent. Use can use acetone, lacquer thinner, even
gasoline if it it BLOWN dry completely with an air gun.

3) Lubricate with ONLY what is commonly called Powdered Graphite.
Not liquid graphite. POWDERED graphite.
DO this liberally, particularly if the lock mechanism has been
completely removed from the vehicle.

4) Periodically, put a little powdered graphite on your key and
work the key in and around in the lock cylinder. BEST manner known
on how to keep locks working excellently and trouble-free for a
long time.

5) NEVER NEVER use any liquid means, particularly not any WD-40-
type liquids. You are simply asking for trouble.

6) Disagree with any of this ?

Print this page out and take this to ANY locksmith and see what HE
tells you to do.

Good lock and better motoring to you.

I hadn't seen those recommendations before, but I did that stuff on my 2002 figuring it was the best way. My lock cylinders broke in half due to a weak linkage flaw they later fixed in 75-76.
I just got some lock cylinders from a junk 2002 and re-keyed them to fit my key. it was pretty easy to change all the little tumblers.
Here's a guide for 2002s, but I bet other cars use the same principle:
http://www.zeebuck.com/bimmers/tech/doorlocks/doorlocks.html
Basically there are little brass slotted pieces (tumblers), and they each have a spring that pushes them out. When the right notch of the key pushes on the slot in the tumbler, it pulls the tumbler inward and flush with the surface of the cylinder, and allows the cylinder to be rotated. Pull out the key, and the spring pushes the tumbler out to block the movement of the cylinder.
Of course I didn't keep my tumblers organized for a straight swap, so I had to keep trying different ones until i found one that would be flush against the cylinder when the key was inserted. I had to modify a couple by filing/sanding them down, to make them work better.
And if in doubt, you can just remove a few tumblers and err on the liberal side of allowing a key that isn't quite perfect.

Anyways, yeah I cleaned mine with brake cleaner and covered them in dry graphite lube. Didn't quite trust the liquid graphite stuff.
The dry graphite lube is a pain to use because it keeps clogging up the tip of the tube and doesn't squirt very well. But its very cool stuff once you get it in there.
After my door locks were operating real smooth with the graphite, i gave it a try to just squirt some graphite in my other locks without disassembling them. It made a huge difference for my trunk and gas cap locks, and they all work with ease, just with some squirts into the keyhole and pushing it in with the key.
That graphite is some great stuff for just a buck or two. I got mine at Redline. Its like i've found the master key for fixing sticky locks, and keep wanting to find more locks to free up.

Yes, that's the best for car AND home door locks! The powdered graphite also works very well for the pine wood derby cars if any of you have kids.:D

Yes, that's the best for car AND home door locks! The powdered graphite also works very well for the pine wood derby cars if any of you have kids.:D

pine wood derby cars have locks?...:D

eh, I just push the little button on my key fob!

eh, I just push the little button on my key fob!DS would do that, but you know British and electronics! :D

hehe 1st read about graphite powder on my 80's ford..

eh, I just push the little button on my key fob!

YOU SOOO FUNNY!!!:mad
Actually, what happens is that you use the remote so much that the locks freeze up when you manually try to lock/unlock the car. So it's good practice to manually do things once in awhile.

In regards to Beastie's comments about the Jag, the 95-97 XJ6's are WAY more reliable than any BMW I've ever owned. Boring, but totally reliable. Probably one of the best buys out there on the used market.
Get an XJR for less than $15k!!!

I used them on skate board bearings, before the sealed bearings even exist.

Wow, how did bearings like that work???:eyecrazy
Were the wheels made of rock?:lol
Wait, don't tell me, you had a friend named "Barney Rubble":lol
Sorry Sushi, couldn't pass it up.

hey need i remind, you have 5 - 6 years head start on me.

The days of metal and clay wheels rock.

you turn + your board still goes straight = road rash!