Mechanic trick to remove broken key from inside lock when other "fishing" methods would not work.
Auto battery was 6 volt in those days, so 12 volt should be tested before actual use.
A long heavy insulated wire with both ends bare goes from battery to obstructed lock. At lock attach length of small solder wire long enough to enter lock skyway when wire is wrapped with electrical tape with only 1/8 inch of pointed tip solder exposed.
Buddy is at battery end ready with wood board to hold bare wire on battery. Get lined up and ready to push solder end against broken key and not touch sides of lock. Have your buddy hold wire battery connection with wood block. Push exposed solder end against broken key, melt solder, yell to buddy to disconnect at battery and let solder connection cool down. Make sure buddy knows not to leave long and melt solder into other parts of lock.
May be able to use method for other needs.
