We decorated our cabin doors on our Xmas cruise. Used suction cup hooks (the kind you would use in a shower). Got medium size hooks, worked great, no adhesive left on the door. Popped them off the door when we were packing up at the end of our cruise and have them for next time. Of course, these will only work if you are hanging a decoration. We had snowmen designed to hang from doorknobs, so for posters and such, hooks would not work.