I don't think it's Petrol based, maybe methanol, I will check. However there is No stains to the paper, you can't tell anything was there, or had been there. I was very sceptical at first, until I watched a fellow do it to his Curse of the Werewolf d/b Quad.
It is more difficult to use on new shiny posters, as the paper isn't as porous; But a bit of patients...