Do what I do. Take it all off the desk and put it on another flat surface. Clean the dust off the desk. Maybe use some Windex. Then bring the pile of papers back and go through them one by one, separating them into

- stuff not needed ever again
- stuff to be filed away
- stuff still needed

Throw out the first lot. File the second. Get to work on the third.

You'll find stuff you'd forgotten about a long time ago. ;-)

I do this about every 3 or 4 months when I can't bear the mess any longer. Now if I could summon up the nerve to take on the entire room! Or the storage building (shudder).