The faint line that remains after ironing will fade with washing....after a couple washes it was gone.....I have only used the black.....if I am marking something that will be washed I prefer the washable markers as they are much cheaper (Crazyart at Walmart now $.50 for pack of 8 different colors) and they wash out great.....but always test whatever marking system you use on every fabric as you may find one marker that will not wash out.