Mom used to color eggs naturally with onion skins, turmeric, red cabbage and other vegetable scraps. The eggs are so beautiful and softly colored.  Coloring eggs naturally is a great way to teach kids to be good stewards of their environment along with a fun lesson in food chemistry.  Every part of the egg is used, even the shells.  Grind them up and scatter about an inch deep into the soil around your houseplants and gardens.  The shells have much-needed natural nutrients!

Now there's no real "recipe", but here's how I do it, the same way my Mom, Mary Nader, and her Mom did it.

In a saucepan, place as many papery outer skins of yellow and/or red onions that you have. Cover with an inch of water.  Bring to a boil, lower to a simmer and cook until onion skins have colored the water, about 10 minutes. 

Use this same method for red cabbage  (just chunk it up), beets, spinach, etc.  Even coffee grounds can be used. 

Strain and add 3-4 tablespoons of clear vinegar to every 4 cups of liquid.   This sets the dye. Don't worry about adding too much vinegar - a little more won't hurt. 
 

To make turmeric colored eggs, place two tablespoons of turmeric in 1-1/2 cups water.  Stir and place in pan.  Cook until it starts to boil.  Remove, let cool but don't strain.  Add a teaspoon or so of vinegar.  Place eggs in dye, stirring to coat.  When you remove the eggs, gently wipe off the turmeric with a soft cloth or run them very quickly under running water.