Hey! Jen Renee.com gives us this tutorial...
This is really all you need, because Kool-Aid has citric acid in it. No need for vinegar! Add one packet of Kool-Aid to 2/3 cup of water and stir. That's it. I used both lukewarm and cold water and it didn't really make a difference with how our eggs turned out. Keep in mind that Kool-Aid powder is pretty messy, so you should do all of the mixing over your sink to prevent your counter tops from turning different colors the next time you wipe them off.
You don't have to leave the eggs in the dye cups very long before you'll see them become quite brightly colored. The eggs will smell fruity at first but after they dry, they smell and taste like normal hard-boiled eggs.
Warning: you about a couple of colors/flavors that had less than desirable results. Lemonade on its own comes out too light (as does the Pink Lemonade) and Grape will quickly turn dark gray-ish. I remedied this by mixing things up a bit. To get a nice yellow, use one packet of Lemonade mixed with a quarter to half packet of Orange. To get light pink, use one packet of Pink Lemonade and add a little bit of Cherry or Strawberry. To turn the gray/brown Grape egg into an indigo color, add some Berry Blue to the mix.
A great idea....
A large muffin baking pan works really well for egg dyeing!