My Kundo 400 Year Anniversary Clock

I was Blessed to inherate this beautiful clock that was my Great Aunt's. It's in great condition. Got it home and was able to get it working. Found information on website www.billsclockworks.com which had the complete instructions. Checked on ebay and am delighted to know that I will be able to replace the "key" which has unfortuantely been lost. The globe became sparkling clean and no scratches that I have found. I am wondering if I should clean the brass as it is quite tarnished. I have been told not to, but "me" I would love to have it restored to it's original luster. The "monetary value" is of little means to me as the "setimental value" out weighs tremendously. But for the sake of arguement ... Should I clean the brass and what would a good suggestion of cleaner be that would not be abrasive but would be easier than the standard "Brasso" ?