There is an ancient bottle of Chinese mustard in my fridge. I believe it was purchased about eight or so years ago and it was opened once. No matter how much I wash it - with bleach and steal wool even! - the sides retain ancient goop and the bottom? uuuugh, I don't even want to go there. I have been forbidden from throwing it away by the other residents of my home, so it lingers, behind the milk and eggs.