Greasing locks?

Graphite (powder) - check out the local locksmith or hardware store.

 

I'd use white grease on the striking plates of the lock, but for the cylinder barrel and tumblers of the lock, I'd use Graphite Lubricant (Hillman)

check at most good hardware stores. You could grind up your own graphite pencil leads (I've done just that, but that was long ago before amazon) but then why keep a dog and bark yourself?

 

Anywhere metal meets metal - for want of a better term, I call them striking-plates since that what they're called in the building trade, but perhaps they're called the "striker" - I've noticed the dealer used white-grease on the door hinges and strikers on my old Corolla Wagon when they did the complete (everything) bumper-bumper service). Oil is all very well for lube, but does tend to run where you don't want it, and it attracts dirt. Use graphite powder on locks or any small catches (I use it on the caps of various LED flashlamps I have where electrical continuity is needed from the cap to the body (graphite is conductive))

 

I use a light shot of silicon from an aerosol can. Maybe every second year.