And lest you think this technique is only for yarn, you can also use it for wool yardage. I don't think this will work as well on cotton.
Let's get started. The yarn on the left is the original color and the yarn on the right is over dyed with Kool-Aid Black Cherry flavor. Before over dyeing the yarn I did a gauge swatch and that is when I realized the colors pooled hideously. Not good for a sweater.
Gather your supplies: a pan or tub or bowl, Kool-Aid and a microwave safe container. Don't know what color will work for you? Here's an article to read and the photos are very helpful. Just remember that in this article she started with white yarn. If you want deeper color results, just use more packets of Kool-Aid. I have used two packets for each skein.
You can see from the above photo that I use 32oz of water. It doesn't matter how much water you use, it just needs to cover your wool or yarn. Heat the water until boiling in the microwave. While that is heating, carefully empty the Kool-Aid into your pan. Carefully add your boiling water and slowly stir to dissolve. No splashing!
Your yarn or wool must be wet before adding to the dye bath. Because I don't want to shock my yarn into felting, I rinse it in tap water from the faucet and gradually turn down the cold tap. Pick up your wool or yarn with tongs and carefully arrange in your pan. Walk away and do something else for a while.
When you come back your wool or yarn should have absorbed all the color from the dye bath and the water should be clear again. Usually by now, the water is also a lot cooler if not cold. Remove your yarn or wool and carefully rinse it until the water runs clear.
Squeeze out any excess water and hang to dry. Voilá! You have successfully over dyed with Kool-Aid.
I am always asked if the yarn smells like the Kool-Aid or if it bleeds. When I block the garment, yes, it smells a bit like the Kool-Aid but faintly. No, it doesn't bleed. I have knitted several pair of socks and then Kool-Aid dyed them and in both cases, my feet did not turn either purple (grape) or green (lime).