The penny should be removed. They cost more to make than they are worth, and do not serve their purpose.
A single penny cost about 1.8 cents to make. There is nothing more to say to argue this point. If it cost more than 1 cent to create something that is worth only 1 cent, you shouldn't create it. End of story.
Even if making pennies was cost effective, it would still be a waste of time and money to create them, because we simply don't use them. Vending machines, parking meters, toll booths, laundry machines, and any other machines that use coins do not accept pennies. They are worth so little, most people do not bother to use them when making purchases. Because of this, pennies do not serve their purpose of facilitating the exchange of goods and services.