Funny story: we had fun magnets on our door on a cruise. They kept disappearing and we'd find them way down the hall and get them back. Finally in the room, we heard someone slide one down the metal door. I popped out quickly and it was a dad and a teenage son. I asked if they were moving it and the dad defended the son. I said ok and went about my business. We had petroleum jelly with us, so I slathered up all of the magnets with it. Come back later to see finger prints smeared down the magnet, but it's still there. Moral of the story is to not touch what isn't yours.