Hi Luisa, I've seen a Calphalon pot get un-anodized>>>
Someone was simmering lemons for a long time (to freshen the air in a rooom smileys/smile.gif
It looks like the dark finish got stripped, leaving a rough, raw-aluminum looking interior.
According to their website, if the pot un-anodizes, nothing harmful got into yor food, and it's perfectly safe, but they'll replace your pot. etc. etc. etc.
I'd just as well not get anything with the hard anodized interior - I figure if I pay that much money for a pot, it should last me a very long time.
I wouldn't want to worry about what kinds of things I can put in a pot, i.e. acidic foods like lemons or tomatoes.
All-Clad stainless all the way.