You can also wash in a large top-loading washer. It is similar to washing in a bathtub except no sheet for lifting, and you never allow the machine to agitate. It's a little easier on the back and knees than washing in a bathtub.
Basically you fill the washer tub with water, adding your soap of choice (Orvis is good), stop the machine, add your quilt, and agitate by hand -- pushing down on the quilt with your hands. When done with the washing, advance the machine to spin (spinning is safe for a quilt), fill with rinse water, stop the machine again, and hand agitate. Rinse as many times as necessary to get all the soap out. After final spin, immediately dry the quilt flat on a large sheet. Fans will speed drying.
You do not want to hang a wet quilt on a clothesline, as the water weight put enormous stress on the quilting stitches. You also do not want to allow damp fabric to lay against itself for any length of time (to prevent dye transfer).