The $20 bill belongs to the owner. Realistically, I'd probably pocket the $20 if I was volunteering to clean up some random lot.
Just wait until the wind blows it into neutral territory. Oh look! $20 in the street!
My opinion on this whole story, woman legally owes him nothing (or a finder's fee) or whatever the law explicitly states.
But she should've been more than willing to share a bit more. Any sort of unscrupulous contractor would've found that box, tore the hell out of the home (on a subsequent visit to continue the job after learning the value,) and made off with the possible half million assets in question.
And she would've been none the wiser, only finding her home in a state of destruction.
Maybe it's just me...In a world filled with liars and greed, I think the woman should've offered more for the guy's complete honesty with the situation. Unfortunately, she didn't, and he didn't take the 10% (not sure if there was any kind of negotiation,) so now they both look greedy.