An interesting story about what went into parking meters fifty years ago. http://www.projo.com/news/content/CITY_HALL_COINS_07-21-11_RHP9PKK_v12.44b99.html
As a rule of thumb people don't put things worth more than a coin in a parking meter. This stuff was junk 50 years ago and will be almost all junk now. This being said I'd give my left arm to have a shot at it. I collect everything and there'd be a lot of stuff I'd like in it. People don't know what everything is worth and stuff that was unusual 50 years ago can be rare now.
Why do I livein Michigan? WWHHYYY! I wish I could trade places with those kids, slip a few coins in my pocket lol