I have the same problem with my Dovo Forestra. What I found to work was baby oil. Seems that a liberal coating of baby oil doesw the trick. I live in south Florida so humidity is always an issue. My Dovo is especially proned to tarnish spots.

To get the spots out I use Turtle Wax Crome polish with a Q-tip let it sit and the buff it off with a clean Q-tip. Takes a while though. I few applications and it is as good as new.