Interesting video on how to crack a mechanical safe. The original gent to do this was a scientist Feynman who worked on the “bomb” in WWII. And was bored. The interesting part is that most of it was figured out from math and social engineering (birthdays, patterns used by the safe combos, etc) than just a brute force or picks. Watch the video in the link below for more.
http://www.howtogeek.com/