Excuse me as I go off topic. Not a problem Nick, 1. These days, the nice new film is in a sealed cardboard box. 2. A habit I aquired in the days of home loaded film and using 'pro-packs', I always rip the end of the leader on removing the film from the camera, you don't need a pen or marker, it takes a second to do and can not be reversed or accidently rubbed out. As an aside, the last roll I processed was so badly reverse curved I could hardly get it on the spiral, there is no way I could have accidently re-used it. Still every one adopts their own procedures, which often seem odd to others.