We recommend washing in tumble washers only. The agitator washer are very hard on Quilts.
Small home Dryers can scorch a large bulky quilt. A large commerical dryer on cool heat would do a safer job.
If you have to wash in a home washer soak and agitate by hand.Spin out water and dry
Dry over clothsline with a towel or small blanket over the line first so you don't end up with a line crease in your quilt till almost dry then put in dryer on no heat to finish drying and fluff the quilt.
Your quilt will need to be washed by hand and layed flat to dry. Fluff in dryer for a few minutes only.