Dust
Dust is a print contaminant and a form of film damage.
Under good handling conditions, a print should never become noticeably dusty on screen, yet many prints are. The easiest ways to prevent dust contamination on prints is to vacuum your booth regularly, store prints in reel bins or cans when not in use, and to NEVER let film leader or any part of the print touch the floor. Once dust gets on a print, it is very difficult to remove. When leader touches the floor and becomes dusty, the dust travels further down the reel, attracting more dust and dirt, which can eventually lead to scratching (especially cinch scratches which are embedded dirt).