Oxi-clean and it is sparkling white.  The secret is to iron it while still heavily damp.  The underskirt lining is taffeta and I iron it wet.  The overskirt if a nylon organza with beautiful lace medallions and accent rows of lace.  The Yves St Lauren  baby doll look was all the rage in the 70's.   The bust measures 36" and the length from shoulder to hem is 57"  There is a detachable train that hooks on making it a great dress for dancing at the reception.  I would consider this dress to be an Ex Small .  Light and airy, it is a beautiful bridal gown for a summer wedding.  Vintage in good condition.