The City of New York used to auction off all the slugs it collected from parking meters. Granted - no guarantee that they worked. But it always seemed short-sighted to me that all that illegal change you collected? ...yeah, let's get that right back into circulation.
The US Mint was so eager to get dollar coins in circulation that they'd let you buy them with a credit card and ship them to you for free. As you might imagine that was taken advantage of.