Although really only mentioned in the subheading of this news article, it's an illuminating bit of news. It says:

Quote:
Tens of millions of yen in cash and hundreds of locked safes have been handed in to police stations across northern Japan by people sifting through the debris of the March 11 earthquake and tsunami.

Granted, much of the cash and many of these safes may have been found by police, fire fighters, and Self-Defense Force soldiers, but maybe not. Numbers-wise, normal people sifting through the debris probably account for the most people, so they are probably the ones finding most of these valuables and turning them in.