Thanks for all your replies. I read about Goo-gone and goof-off elsewhere on the net, but I live in Denmark and I haven't had any luck finding the product here. Do you know of a similar product in Denmark/Europe? Otherwise I will just have to order it outside the country. And no, I didn't do anything that warranted a drawing, I simply had it with me on a festival and a guy thought it funny to make a drawing. He actually drew a huge penis, half the size of the front of the tent, so you can properly imagine what it looks like when I lies in my tent....But I can only smile at it, done is done
But it also makes it kind of hard to overdraw with just a black dot or something else.
I hope you can recommend a danish/European product which might do the trick, I figure my modded tent might make some people look strange on the next trip I'm on.