Use your regular detergent and wash it on delicate. Turn the washer off and let it soak for a while before it agitates. You may want drain off that water and wash it in fresh water if the smell is really bad. I'd be careful of too many additives, though some white vinegar might be okay. I would spin it on normal to remove as much water as possible, then dry it in the dryer until damp, then lay it out. I wash a 50 year old quilt totally handmade that way.