i kind of though cold water would help set the colors...when i've used crayola markers i've always then washed...yes...washed...not just soaked but put in the washer...with warm water and detergent...all marks came out. but i always test every fabric i'm going to mark because just because it came out of this peice does not mean it will come out of the one next to it. i don't know that just sitting in cold water is going to accomplish anything