Collections for the Sims 2?

I had to recently reinstall the Sims 2 and all of the clothes that I had categorized (based on clothing for different sized skins) is gone and I have to do it all over again. I have downloaded a bunch of clothes that were already in a collections file. How do I back this up? I am just talking about the collection files so that if I move my custom content onto another computer then I can just reinstall the collection file and not have to worry about sorting through the clothes and trying to figure out what sizes they are or anything. Thanks in advance.