The dark drawer is that place in your desk where all the agglomerated crud of daily life is to be found. The rationale for placement in the dark drawer is a part of what determines a dark drawer in the first place: it is the repository for all sorts of clutter which you might just need again; the sometimes marginally useless knick-knacks which tumble out of Christmas crackers; the nub-end of a packet of throat lozenges in the aftermath of a bad cold; a fuel bill which you may get round to claiming as expenses if it doesn't decompose and crumble into dust in the intervening period.
Dark drawers tend to be layered in the way in which rock strata are layered, or, a more apposite analogy perhaps, the way in which the layers of the nine cities of Troy were successively uncovered by Heinrich Schliemann.
A careful perusal of a person's dark drawer will reveal a plethora of information to the trained eye: they are a sociologist's paradise. The garbage which a person throws out is revealing of their past habits of consumption; the trivia which a person retains are indicative of their anticipation of their future needs.
| 
