Paper. Trash. Paper. Trash. Paper. Trash. We've been disposing mountains upon mountains of paper trash already that I cannot track how much! Just look at that piled pieces of paper on your desk and you will see what I mean. At least have the decency to put these documents in their proper shelves and spare your office mates the eyesore. Not only is it unprofessional-looking, it won't make a good impression on your office mates and your bosses, either. After all, less paper means a greater peace of mind, right?

So what could you do to clean up the mess? Well, for one, you could limit yourself as to where you will put the paper. a small folder, perhaps, or a whole desk. Just make sure than when the shelves fill up, of there is no more space in the folders, you will take time to look at each piece of paper and check if they still have any use to you.
Better still, ask help from someone. What I notice is that many people find it hard to declutter because they still think that the pieces of paper in their shelves are still important. Lines like "I still might need this" and "I cannot throw this just yet" are so common that, in effect, you have not decluttered and just wasted time poring over your documents. With the help of a discerning workmate, you could tell him/her why you still need the document and he/she will judge if it is still worthy of keeping or you are just hoarding.
When you finish separating what is still needed from what is not, put back the still-needed ones in their original containers, clipping relevant files. Also do not forget to recycle what will be thrown out.