http://coinapps.com/base-metal/coin/calculator/
Until folks are ready to accept that money is unnecessary, some form of coinage will persist.
Although we could do it an any given tuesday, the crowd just isn't ready for that.
They are ready to reevaluate the value of money.
To replace all the coinage in america would be a logistics nightmare, easier to just reassign the the old coins to the new value, imo.