It turned out better than I had expected. I won't need anymore eggshells for at least a year. McD's gave me a bag full. Then Anne and I went to a new, large pancake restaurant ; it was packed. I talked to the owner, and he went back into the kitchen and brought out a humongous bag full.
I just now washed them all in the downstairs laundry room sink filled with hot water and a half cup of bleach (I thought it best to be careful since I have no idea of who/how they were handled) and rinsed them in a refilled sink of hot water. I brought them upstairs in the big black bag, took them out by the handfuls, smashing them with my fingers, and put them in a BIG pot that Anne has. They filled that pot to the brim.
I want to bake them in the oven for 15 minutes or more at 350*, but I have to wait for Anne to get out of the shower because I don't how to turn the oven on.
Once they're done, I'l put them in a paper bag and smash them with a rolling pin until they're small pieces.