Maybe keeping your coins in a change purse was a European custom. My grandfather used a change purse when I was a kid (1940s). He would open it up and give my brother and me a few coins. He was a Hungarian immigrant.

Come to think of it I had a wallet that had a snap lock section for coins when I was a kid.

Perhaps this may cast some doubt on the movie version's reason for Gimpel getting caught. I can tell you from my own experience researching the attempted escape of Otto Kretschmer that there are more than five versions of why the escape tunnels were discovered that have been published in newspapers, magazines and books.

Coins were a lot more valuable then, and people wanted to carry them in such a way that they would not get lost easily. A lot of people were only making twenty-five to fifty cents an hour in the 40s. If you lost a nickel back then, you might have to walk five to ten miles to get home.