It's not always possible to remove kool aid stains from carpet. All “red stains" are difficult to get out. Red coloring used in pop, candy, and other foods generally doesn't flush out with water. However, if you try the methods used by professional carpet cleaners, you may get that stain out.
First, use a shop-vac to suck some of the kool aid out, if you can get to the stain quickly. This can stop the spill from entering the carpet fibers. Getting out some or all of the remaining stain takes time.
Start with Dawn dishwashing detergent - the original blue type. Add five or six drops to two cups of warm water. Dampen a white cotton cloth with this solution and lay it over the stain. Then place a clothes iron on top of it, set on “low".
Let this sit for fifteen minutes, and don't press down. The red stain will start to wick up into the cloth. You should see red on the cloth. Fold it to use a clean part or apply a new cloth, and repeat the process.
It takes patience to get red stains out of carpet, but even year-old Kool Aid stains have been removed using this method. Repeat the process again and again until there is no more transfer of the red stain to the cloth. Rinse the spot with water, blot it up, and dry it quickly. Quick drying prevents any stain deeper down from wicking up to the surface.
To summarize: use clean white cotton cloth (several), low heat, and don't press or rub. Let the color wick up into the cloth at its own rate, then rinse and dry the area quickly. You can, at the very least, lighten Kool Aid stains and other red stains in carpet using this technique.
Steve Gillman has worked in the carpet cleaning industry for years. For more carpet-care information, and specific stain-by-stain removal instructions, visit http://www.HowToRemoveCarpetStains.com