Nasheekah at Weird Jews 2 asks the question: What do you do with an etrog that has fufilled its holy duty?
Sure, anyone might think of a Havdallah spice box, but etrog-infused cocktails? Looove it. But the lulav’s a little large for a swizzle stick, nu?
You can chop up the etrog, mix it with some vodka and sugar and let it sit. By next year you can have etrog-flavored vodka in your sukkah.