Matching keys/locks, storage and entry doors

[jujustad]

Unfortunately I too have 2 entry doors with different keys and another key for storage compartments. Until I can rectify that I put some red nail polish on the key and the door lock cylinder that it goes to. I also put red polish on the storage compartment key and put a dot on the lock cylinder so that I always know which way to position the key to insert it correctly. I touch up the polish every year and it works great.

[mikereidjr]

I would like to do this as well, where do I buy the cylinders?