How Mirror Master Escapes Jail

This panel from an old comic book The Flash explains how Mirror Master escaped from jail.
"I had tiny mirrors cleverly secreted on my person when they put me in jail! I could have pulled an escape immediately--but I wanted the right moment! I guess I have my vanity..."
I have seen enough television shows to know how jailers process people for prison. So where were these mirrors "secreted" on his person?
I guess his "vanity" means not wanting to take them out in front of people...
Hmmf! Mirrors secreted on his person...