I have bought and tried Orvus quilt soap from Missouri Star Quilt Company. Works pretty good. Here is their description:
Founded by Proctor & Gamble Company in 1932, Orvus' secret formula has not changed in 85 years. Oruvs has been trusted by the world's most prestigious museum curators to clean and preserve prized quilts, historical fabrics and tapestries. Orvus is 100% phosphate free, dye free, PH neutral, biodegradable and fragrance free. 1 oz sachet package is ideal for a singe standard sized machine wash load or for washing a bed sized quilt. Recommended by the American Quilter's Society for cleaning quilts!
Great for delicate fabrics, quilting cotton, fine linens, wool, fleece, needlework, heirlooms, crochet and everyday fabrics.