I'm sure I've read of the eggshell ploy somewhere, but I can't find it offhand. I definitely saw it in the My World and Welcome to It episode where their new cook was afraid of electricity. Based on Thurber cartoons. I'll have to google for the actess who played William Windom's wise and compassionate wife. This JoC recommends not putting a lightly beaten egg to clarify the coffee, because it impairs the flavor of the coffee. Kephart says that only a few old timers now take the trouble to roast and grind their coffee "berries" with a frypan and a pistol-butt.