I left the ink in fabric for over 3 months and it ironed out completely....believe me I was a little worried when I realized that it was still on the fabric after all that time. I too have tested it by washing the fabric to see if it washes out and it has on every piece that I have washed. However, if you are concerned about this, always pre-test...it takes just a few minutes to mark, iron, then swish in a little water and detergent. It can save you lots of anguish later on.