My 16year old daughter is determined to cover her freshly painted bedroom walls with all manner of posters. She's stuck them up using sellotape, which I'm not happy about as I forsee a lot of rips in the wallpaper when she comes to make changes (which she will). She says blu tack makes just as much mess --- so has anyone got a suggestion of what to use to stick them up? She doesn't want them all framed (nor do I, on grounds of cost/transience) so ideas welcome.