Why do we still keep using Pennies and Nickel?

Soaring copper prices are pinching the penny makers. It now costs 1.3cents to make a penny and 7.7cents to make a nickel. But there's an environmental cost, too, to minting new coins- namely, copper mining and refining that involves huge amounts of power and water. Coinstar estimates there are some 150 billion coins going unused in US. => $10billion or $90 per household, stashed in mason jars and under couch cushions. Cashing in just 10% of this amount would translate into sizable environmental savings as show in the table below.

Savings Of	Equivalent to
Water	82 million showers*
Energy	4.1 million 60-watts bulbs**
CO2	12619 cars removed annually from roads***

* 40 gallons each
** Over average life span of 1000 hours
*** Assuming average mileage
Source: Business week May 2008