My two most recent crafts-of-the-moment are dying yarn with Kool-Aid and spinning yarn with a drop spindle. Soon I will combine the two activities by dying the unspun wool (also called roving) before spinning it, but I haven't quite gotten started on that. I have two pounds of roving just waiting to meet the myriad of dyes I bought at an art supply store last weekend. Real dyes, these - not Kool-aid. They are so real that I also bought a face mask to wear when mixing them because it is dangerous to breathe in the dye powders.
But Kool-Aid (or any un-sweetened or sugar-free drink mix containing artificial colors), which is harmless enough to drink, is a great dye and I will continue to use it even after dipping into the hard stuff. It is easy to get, easy to store, it smells good, it's not too expensive, containers used aren't contaminated by harmful chemicals, and the worst that could happen when using it is your hands could get stained fruity colors for a little while.
Kool-Aid only works on protein fibers, though. Protein fibers are any fibers that come from an animal or human, such as wool or hair. However, Kool-Aid will also dye nylon, a synthetic fiber. The reason for this is because nylon, with its silk-like molecular structure, is a polypeptide, which is the molecular shape of a protein. Other synthetic fibers like acrylic do not bond with Kool-Aid, nor do plant fibers such as cotton.
More information about the process of Kool-Aid dying can be found at the websites below, which is where I learned how to do it.
The article that started it all for me:
These articles have illustrations of the process:
A fantastic colorchart:
If none of the above links seem helpful to you, try doing an online search using the phrase "yarn dye kool-aid" or something similar.
Some tips I'd like to mention:
1. It is not necessary to add vinegar when using Kool-Aid or other mixes that list citric acid as one of the main ingredients. Vinegar is necessary when using food colors or jello - they need the vinegar to be the acid.
2. When dying wool, it is important that the rinsewater is about the same temperature as the yarn. If the yarn is still warm from being dyed, rinse it in warm water. If the yarn is cool from being out at room temperature for a while, rinse it in cool water. This prevents the yarn from sticking to itself and becoming matted (which is known as felting).
3. Nylon yarn does take Kool-Aid type dyes very well. I have washed and dryed multiple dyed nylon skeins and there was no color loss.
Or you could just order one of my well-instructed yarn dying kits from Craftlings at http://craftlings.etsy.com.