Cleaning the Outside of a Discolored Pampered Chef Pan?

How do I get rid of the copper colour on the outside (sides and outside bottom) of a stainless steel pot? I let water boil down on my wife's Pampered Chef pot, and although it looks like there is no damage except for a couple tiny black marks inside the pot (which I've read on the site to treat with vinegar already), the outside is a copper colour and I would like to know how to get it back to shiny silver, and if it's still safe to use.

Thanks!

By Luke from Saskatchewan