I've been working on this riff on an Asian noodle soup. As the final garnish, I want to drop an egg yolk in the middle of the individual serving bowls of soup, to warm for a couple of minutes in the boiling hot soup and to burst with the first stir. Sounds simple, right? It's giving me a problem though.  I use the whites in the soup. I need to separate the eggs at least about 10 minutes before I drop the yolks. Separated yolks are really touchy, they want to break before their time. That they are at room temperature (for reasons that should be fairly obvious) doesn't help. I've been holding the yolks in little custard cups. I've tried putting a little water (hot and cool) in the cups, I've also tried broth from the soup. Even doing those things, the yolks break as I try (ever so gently) to drop them onto the soup.  Any ideas? 
You don't actually have to refrigerate ketchup. Once it's opened it's good for a month or so with no appreciable change. After that the flavour and colour starts to degrade, but it's still safe to eat.  Worcestershire sauce is fermented for more than a year before it's bottled, so it will change at a much slower rate than an acidic, but unfermented sauce like ketchup. Still, it's only good for a few years after it's opened. 