Anywho, I had a bag about the size of a standard large paper grocery bag...full (stuffed) of eggshells. Needed to make room in the bag.
When I kept chickens, I also collected their shells to feed back to them. I would keep a large plastic (yogurt or margarine) container under the sink and squish them into it (wait til they are dry). Then every once in a while I would take the pestle (from the mortar) and really crunch them. Then sprinkle it on the hens feed.
Never thought about using them in the garden. Thanks for the tip! Of course, don't have as many shells now as I have developed a sensitivity to eggs... gads I miss them! But still use them in cooking.