Downsizing, letting go, organizing, simplifying.

I have a large stack of boxes full of papers and books that I brought home when I closed my office.   I went through most of the things when I packed them, but it got to the point that I just had to go ahead and put the things in boxes.  I had to get out of there.    It was just the need to make the break and to get my things out of that room and out of the building.   I had no place to put them but in the middle of my living room floor and there they have sat since the beginning of December.   I also had some Christmas decorations and a few other boxes to add to the stack.   Today I managed to get some of the mountain of boxes rearranged and organized a little differently and I managed to do a good bit of house cleaning and washing.   I am tired and feel at last I have begun the process of reclaiming my space.   I don't know what to do with my boxes from my office.   I kept a lot of files because if I continue to practice as a therapist I need access to some of this material.   I have collected different books that I use with clients in bibliotherapy.  I have also collected a variety of manuals and program development materials to help me put together programs and proposals.   I wish I knew if I were going to need these things.   I would love to toss a lot of it.  I doubt I will ever look at it again.   I am at a loss as to what to do with it all.   I really don't have room for it at home.  I need another room!   Any suggestions.   I am really focused on downsizing my clothes and some other collections that I have grown throughout the years.   I had a friend when I was a little girl who had the skill to totally clean her room when the time came.  She could through things out when she didn't use them anymore and she kept everything neat and clean.   Even when I tried to throw things out so my room could look like hers, I never did acquire that skill.    I am a hoarder, a pack rat, a collector, a save it you might need it kind of girl.   I wish I could be free of that and let go.    That is one of my goals for this year.   Throw it out if it isn't used, if it is old, or worn out, if it is a duplicate, if it is dated and stale.      I am just going to keep on trying!  Any suggestions?