Eggshells in French Press Coffee?
Geez, does this ever take me back in time. Our family used a wood stove until about 1947 and every morning coffee was made by heating water in a pan, throwing some ground coffee into it, letting it settle, then pouring. Egg shells were used. Certainly no lack of egg shells on the farm.
I've never had a fondness for French Press Coffee because of the muddiness. I thought perhaps that was one of the reasons people like it melita-style.