There are a wide variety of uses for both tarnished and untarnished copper materials. Of course, untarnished is always preferable and it’s essential to maintain purity during the processing to ensure that future products retain high conductivity.
Copper was discovered around 9000 B.C. It is considered to be one of the first metals to be used by mankind. One of the many reasons that it is still widely used to this day is because it can be recycled so that any trace of its original use and form is gone.