After cleaning my cast iron, I have turned to my all-clad mc2 skillet, which I had let the bottom get to solid black, up to the rim. I let this happen once before, and put it into the neighbor's self-cleaning oven. I later learned, I believe from @boilsover, that this is a Very Bad Choice with clad pans. The finish was totally dulled, but the pan seemed to work fine after.
But I let the situation get horrible again after about 7 years including 3 in my pandemic-pit of a kitchen.
Two rounds of carbon-off later, most of the carbon is off. But the metal has a whole new texture!
The bottom of the other MC2 pan which I purchased at the same time (2002!), but which rarely gets used being a 6qt sautee pan, doesn't look anything like this. It still looks like that brushed-finish-thing they were doing back then.
I need to quit messing over these good pans . . . .