Colenso BBDO, Auckland advertised prison break (the show) by placing special bars of soap in public restrooms all over new Zealand. On one side there was a key-imprint, and on the other the shows details. I wonder how long the soaps message lasted.
"We embedded a key imprint and the show’s details into bars of soap. They were then placed in public bathrooms all around New Zealand, with the details side facing up. Upon washing their hands the user would discover the underside where a key impression was hidden.