Well from the appearance to get it to shine you will most likely have to polish the crap out of it and remove a lot of the details in the process...
Beyond that a cotton rag soaked with Brasso is easy enough, even though you said you didn't want to do it yourself... You most likely wont't get a mirrored shine to it (without tons of hours or mechanical buffing) because of the surface but you can clean it up real nice without much work...
As said a jewelry store is probably your best bet, but it will probably cost a pretty penny if you want shine...