nordicware "natural aluminum" which turns out to even be documented as "discoloration will occur due to the cleaning agents used in automatic dishwasher detergent" and discoloration turns out to mean "grey and white mottled surface with an odd texture" (so probably not *just* aluminum oxide, but definitely an "it's not supposed to look like that" result.) Since dark vs light surfaces are supposed to matter for cookie baking (no I haven't dug into the theory on that one) it seemed worth fixing, and the result was definitely back to shiny....
no subject