I have been saving my onion skins. Lately, we've been having a lot of onions and mushrooms sauteed with olive oil. So good. If you don't eat a lot of onions, you could go to the grocers and fill a bag with skins and a couple of onions...It makes the most beautiful deep red natural egg coloring! First, I place all the onion skins in the pot, then the eggs and cover with cold water and a little vinegar. I bring the pot to a boil, then reduce heat to medium for 10 minutes, the eggs will be hard-boiled...I like to leave them in the pot for a while longer, so they get a deeper red. Much better than food coloring you buy at the store! I'm trying to avoid all fake stuff... I took the photo above 3 years ago when I first tried it. A bit blotchy, but I love it, the eggs look even better if you rub a cloth with a dab of oil on it...shiny. And, oh, yes, scrumptious when you open them and add a pinch of salt.