They even make a special pen for it: http://www.alimed.com/viscot-pre-surgical-mini-skin-markers.html http://www.alimed.com/viscot-pre-surgical-mini-skin-marke

They even make a special pen for it: http://www.alimed.com/viscot-pre-surgical-mini-skin-markers.html http://www.alimed.com/viscot-pre-surgical-mini-skin-markers....