We did NOT remove the wallpaper border when we put up glass tiles behind the stove we just cleaned the area with grease remover and laid down grout OVER the border and put up Glass tile sheets, sealed the grout and they have stayed put that way traveling all over with no problems, I guess their is also glass tile sheets that have adhesive on the back so you do not have to grout as well but could not find those at Home Depot so we grouted them, it looked so good and has held up well we will do the same in the Bathroom, If you do a search on "backsplash" you can see mine