Onion skins and greens are not the only vegetables the pioneer children used to dye eggs. They probably used beets for pink and red, blackberries or Concord grapes for purple, chestnuts for blue, dandelion flowers or crocuses for yellow, rhubarb leaves for green, and sassafras root bark for orange (available at health food stores).
Gently boil one of the above-mentioned items in a large pan of water until the water is colored, remove the item (if desired), then add vinegar to the colored water (about 1 tablespoon per 2 cups of liquid). Gently lower raw eggs into the colored water and simmer to a hard boil (10–15 minutes). After the eggs have cooled, rub a dab of cooking oil on them to make them shine.