Shells such as clams are not decomposed in the soil. Crush them, then add to the bucket, and minute levels of calcium, magnesium, and other minerals will be released. Coffee grounds are good for the compost. Egg shells will decompose faster if crushed. Large pieces of food should be broken down into small pieces to hasten the fermentation process. Be sure to expose seeds of an item (such as cantaloupe) when adding to the bucket.
Adding compost to your soil is considered essential for sustainable food production. Slim down your trash with this list of 100 things you can compost. No 51 will either shock, surprise, or disgust you!