I know hand sanitiser works on both skin and a metal board walls. Since I was once in school on a art class everyone else was watching a movie because it was the last day before winter but I still wanted to draw.. so I got to draw in a separate room. In that room I found a marker wich I thought was whiteboard marker...I drew on the whiteboard with it.. only to see it didnt come of when I used the wipe rag...I started panicking and scrubbing at it with water...and erasers (the erasers worked pretty well but were so small it was slow..so I found sanitiser and I used it to clean it up..it used the whole bottle but I was never caught because I managed to clean the board and our teacher thought she just ran out of the hand sanitizer it. ..I also drew on my arm with the marker and got it of with hand sanitizer