you can try soaking them thoroughly it has to be thoroughly that means several times with luke warm water it's an outside chance but I have stripped entire pieces of wallpaper like this not often but a poster you might just manage it's worth a try you have nothing to lose

I don't think there is any way to do this. Sorry.

I'm thinking about changing my room but I have wallpapered some posters on and don't want to damage them when I take them down? Is there anyway I would be about to get them off without damaging them??