The next time you think about leaving a dead ball on a court for throw away, think about REBOUNCES.COM. This organization helps recycle dead balls into practice balls instead of putting them in landfills. Note: They only accept balls of reasonable quality (no doggy toys or mud/water damaged balls).
Very cool program. They will even pay for the shipping. But they only accept from 100 to 500 balls per shipment. So, if you don't have 100 balls, join forces with your friends or other players in your group, club or lessons. http://rebounces.com/page/Home.aspx