Is it OK to put wd40 in a lock?
Do not use WD-40, WD-40 is a solvent, not a lubricant and will, in fact, remove any type of lubricant that is in the cylinder. Use a lubricant that has a silicone, graphite or Teflon base only. Make sure the lock cylinder is facing up and spray or pour the lubricant into the cylinder.
What do you do when your door lock is stuck?
for a stuck button, try turning the handle while pushing and holding the lock button, and then jiggle the handle to see if it helps. If the door lock is stuck in an unlocked condition, try to see if the door will lock when it is ajar in case of an alignment issue.