One thing I do believe in is a scheduled clean up. This is where I basically file, throw away, scan or delegate things off my desk. It is a thorough process and leaves my desk a blank canvas again. Not efficient and definitely not 5S! I think we can all end up with piles of paperwork (except the few who scan their papers, preferring to work paperless as much as possible). It is good to control that at times and by scheduling it I find that works for me.