Greetings,  I thought I had responded to this earlier, but it seems
I neglected to hit 'Send'.  I see expert advice has been offered,
but just for the heck of it, I'll go ahead and add my two cents.

The vintage wooden boat crowd (and the modern sailing crowd) here
in the San Francisco Bay Area really like Prism Polish. It cleans
a multitude of metals, Fiberglas, and plastics in a way that does not
degrade them.

I have used their creme polish and like it tremendously.  It is very
much designed to not do things to metal that will accelerate tarnishing
or other degradation. We use it on old bronze and brass as well as
other metals. It really is a great product.  Here's what they say on
their web site:  http://www.prismpolish.com/ 

I am just a happy customer with a couple of old boats and a love of good
metals.

Yours,
Lorna Joy Shashinda
Alameda, California