Not long ago, a friend arrived home to find that she had left her house key at work. She called me, the handy yet always platonic guy she knows, and I picked the deadbolt. She very gratefully asked how she was to lock the door when she left the next morning. Good thing I live close by, or I would have had to suggest I stay.
While this tip is NOT to be used for illegal activity, if you have picked or bypassed a deadbolt, but need to lock it again from the key side, if you can't leave the plug in that special nether region where the bolt is withdrawn but the pins haven't reset , you *could* pick it again, OR
Glass-reinforced packing tape! Also known as filament tape. Works like this, and only if the deadbolt has a knob.
1. Cut a piece of tape that will reach from the knob, through the door seal, and leave enough to pull on outside.
2. Set the knob so that the T handle is as vertical as possible while not throwing the bolt.
3. Adhere the tape down the side of the T opposite the bolt, so that pulling it throws the bolt. Do not wrap the tape completely around the handle!
4. Very important! Fold the rest of the length of tape lengthwise on itself so that no adhesive areas remain.
5. Close the door with the free end running around the edge of the door through the seal, being careful the tape doesn't block the bolt.
6. A strong but steady pull turns the handle, throws the bolt, and the T handle turns such that further pulling peels the tape off. You retrieve the tape intact, save the day, and are then free to not make any move on your platonic friend that would only confirm that you have no chance. It's better not to know.
Neighborcat