Coffee and Caffeine FAQ

Thanks so much, fellas. I am a thorough Marx brothers addict, and in one of my favorite movies of theirs - "The Big Store" - Harpo adds eggshells to the coffee maker's basket for Groucho's breakfast. This ALWAYS puzzled me, but now I have the answer thanks to my fellow java aficionados.
As a chemist, I agree that the calcium compounds in the shells would likely neutralize a small portion of the acids. Naturally, if you crush the shells more, there's more surface area to react, and slightly more neutralization.
Avoid decaf, unless it's by water process! They extract the caffeine with dichloromethane (or methylene chloride as it's also known) which is a known carcinogen. But then, why drink decaf? Don't we all love our Vitamin C? (C for caffeine... ;-) )