how big is it?
If it's fairly large, I think I would use a large front loading machine and use cold water. I would go to a laundromat, if necessary.
I think that type of washer would be better than a top loader.
But I don't know - this is just a guess on my part.
If it was little, I would put it on a sweater drying rack thing and then I would pour water through it with the dark color on the bottom until it ran clear.
I really don't know for sure what would happen.
Do you have any scraps left that you could make a mini quilt (like 6 x 6 inches) and experiment? You could just layer it and zig zag the edges and try a few things?