Sometimes, you just have to clear your desk. Pile it all up in one stack and go through it – even if the result is more stacks. Throw away, scan, or file anything that doesn’t need to be in your way. If for no other reason that the psychological benefit, periodically, you need a pristine workspace.
Go one better, though. Anything that can be paperless, make paperless. Invest in two items: a sheet-fed scanner and a shredder. Use them in that order, and clear clutter like a bulldozer on a lint pile.