Police in Grand Haven are appealing to people to surrender their instant riches after a box with $30,000 fell off the back of a truck.
Authorities said drivers stopped last Thursday to pick up cash for themselves.
Only $2,500 was immediately recovered and returned to the owner, who had forgotten that a cash box was on the truck's bumper.
Traffic was backed up on U.S. 31 after money hit the ground.
But by Saturday, more money was trickling in. The Department of Public Safety said two teenagers turned in $630, and a woman gave up nearly $3,900.
The department says on Facebook: "We commend you for your honesty!!"