I came across this a while back, but was reminded of it recently. One Man’s Trash . . . The link is a review about a book on compulsive hoarding. Hoarding I take to be more indiscriminate. Collecting has more of a purpose, rather than just anything. I can be a bit picky when it comes to stationery and there are papers/inks/pens, etc I wouldn't touch with a barge pole.
Bookmarks