Some of us are clutter people, I can't thinks too straight without stuffs all around. Not a problem, except, sometimes one needs to walk and not show up on some reality TV show as a before picture. I think people with neat desks will never understand those of us with messy ones any more than extraverts will ever understand introverts.
I use reminiscing while sorting to sort must haves, like to keeps, and mostly indifferent to stacks when moving or purging. I'd suggest talking through a similar system with her. Maybe special boxes for the "best of" keepers. And keep a trashcan/recycling box handy, at least from my experience if I keep the "whatevers" I'll have to review them again before they go away.
