I have a tin-lined copper sauce pan from Rameria Mazzetti, which I love, but I notice the tin discoloring. I have read that it is normal that the tin becomes dull/gray when you cook in it.
My question concerns the lid: it has gotten some weird brown patterns after cooking with it a couple of times. Is this normal? Can it be cleaned without damaging the tin layer? A wipe with a sponge and soap doesn't do anything.