Every so often my bike lock seizes up, very frustrating and a bit dodgy if I’m out and need to unlock it before coming home. In the past I’ve got the guys at the bike shop to fix it for me but there’s an easier way, a total home fix.
All you need is a bit of graphite – pencil lead – and ten minutes. The lock in the pictures was completely frozen and had been for weeks.
Step 1
Break the pencil lead into the lock. I slid the refill leads for a mechanical pencil into the lock, and broke them off at the level of the top of the lock.
Step 2
Insert the key and wiggle it back and forth as if to open it. This may take some time. The key will crush the graphite to a powder that will “lubricate” the lock and unfreeze. Add more pencil lead if it’s really not moving. 
Step 3
When lock starts to turn, pull it open! I fixed two bike locks so far with this method, for less than a euro.
I am not a tourist 