Picked up another bag of eggshells at McDonalds about an hour ago.
The world went around a lot faster this time. I lined the pan with aluminum as "steffpeck" suggested and filled it with unwashed eggshells. Stuck 'em in the oven for 30 minutes on 450 degrees. Took 'em out; put 'em in a bag with the others, and, Voila, Done!
BTW, Anne's so proud of me. For the first time ever, I turned on the oven, set the temperature and the time.