Employ people in the inner cities to beautify their own surroundings by building parks, planting trees, salvaging abandoned buildings, the list goes on.

Property values go up and pride in the neighborhood helps crime rates go down.

Some citizens could be sworn in as peace officers, assisting the police.

I live in a city where we have two branch libraries in what are considered to be very bad parts of town. The people in these neighborhoods are very protective of their branch libraries and don't take kindly when their own--including the gangs--mess with the libraries and parks.

Incredibly good cost-to-benefit ratio with this, I suspect.