I came up with the bright idea to sear a pork shoulder in a Descoware enamel-coated cast iron pot. The meat was already treated with a rub of many spices, including plenty of brown sugar, but there was no fat or oil of any kind. I used the pot all day, and made a fabulous faux pulled pork after 7 hours of low-temp cooking. But the bottom of the pan is still covered with stubborn black crust. I am kind of upset about it, as this is actually part of my mom's Descoware set that she received as a wedding present long ago. I have tried scrubbing with baking soda and a gentle sponge, as well as overnight soaking with delicate dish soap. So far, very little progress. Can anyone give me further tips? I can't give up yet.