G.B.
Good Morning, I.:
Here is what I do:
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 does take some patience, but even year-old Kool Aid stains have been removed using this method. Just keep repeating the process 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 coming up to the surface.
I got this from the website: http://www.howtoremovecarpetstains.com/ and it does work. :)