Water soluble thread. Perfect for basting and applique. Not recommended for swimsuits. Vanish water-soluble thread is created from a special blend of ingredients that allows the thread to be sewn or quilted and when immersed in water, dissolve. Vanish-Extra is for quilting on longarm machines. Special Notes: We recommend that you immerse your quilt/project to allow Vanish to thoroughly dissolve. Warm water will speed up the dissolve time.