You can buy spray adhesive but it is tricky as you get one shot to stick the paper to the trashcan. So the best thing is to make it bigger and once glued, trim off excess. The best think to use is Elmer' white glue but it doesn't stick to plastic or metal very well. Wallpaper paste won't work either. So spray adhesive is your best bet. Do it outside where there is good ventilation, the stuff is powerful.

I have some really pretty leftover wallpaper and I would like to use it to make my little trash can for my dorm prettier. The wallpaper is quite thick and soft, bathroom/kitchen wallpaper. It's unpasted. Thanks!