The sail that I was referring to in that thread has been washed and although it had no effect on the imprint (nor the paint I tried to use to cover it up), it came out of the wash perfectly fine. I did not however try to run it through the dryer (because it still had the paint on it). I imagine it’d be ok…
carefull!!!
i've tryed to iron a carpet which is of the same fabrick with the royal tent and it melted !!! 
To iron, you might want to soak it in water, iron on low heat, with a towel or washcloth over the rug/sail/tent/etc to protect it from the direct heat.