Hi @steem-samiam! It was so long ago but I believe she just put them in the garden and tilled it in. She had a stove percolator (fun fact..they still sell them) and would save the grounds and eggshells. I remember her adding them together in a can and adding the contents weekly to her garden. It wasn't unusual to find eggshells in the indoor plants as well. I did not inherit her green thumb so much. Her gardens were her biggest joy, other than her nine children (I think..lol). I bet that was a mess but I can see where it would make a great exfoliant too.😉