You might try a paste
of Barkeepers Friend & water.
Not exact matches
My enameled cast iron dutch oven has finally gotten stains that even
barkeepers friend can't remove — but this recipe was the best thing to ever come out
of it!
As to how to clean pots without affecting the finish... use the kind
of abrasive you would use for glass - top stoves or perhaps something called
Barkeeper's Friend -LRB-?)
I like to use
Barkeeper's Friend powder to scrub the first layer
of tarnish and grime off brass.