Have you tried hydrogen peroxide? It is great on carpet! I have gotten most everthing out of my light tan carpet using it. Just pour a little on the stain and let it sit for a few minutes. Dab it lightly with a clean cloth. If you are getting any of the grape juice up onto the cloth then you can tell that it will work. It may take more than one application, but would be well worth the try. Best wishes!
at 10:11 PM on Feb. 1, 2011