How to Unlock an Interior Door
- 1). Use a small slotted screwdriver to unlock an interior door with a slot--latch. Some interior door locks have spring loads that need a twist to open. This type of knob comes with a key tool that's small and easily misplaced. A slotted head of a screwdriver with a long and slender post fits into a receiver inside the lock that resembles the head of a screw. Catch the screwdriver on the slot and turn clockwise to pop the lock open.
- 2). Use a large paper clip to open a pressure spring lock. Unfold two of the bends on a large paper clip and straighten into a post.
- 3). Slip the straightened end of the paper clip into the hole in the knob or lever. Push against the pressure fence inside the lock and turn the handle or knob in either direction. The lock will pop open.
Source...