I work in a school, so I'm always finding Lego outside or in the halls (one of my students has a penchant for getting angry and throwing his Lego, it's great...). I generally leave it for whoever lost it to find unless it's somewhere that someone will fall on it. That's how I wound up with my favorite desk citizen: a sort of relative of Unikitty made out of one of those yellow 1x2 bricks with the face on them, a black 1x1 round plate, a blue 1x2 brick, a couple little slopes and other round plates. It's kind of really adorable.
I didn't get to rescue Emmett's hair before the janitor swept it up. :\