Sheri, unless you can see a University Products or Gaylord stamp somewhere on those 3-ring binders, assume they contain PVC’s or other volatile plastics detrimental to preservation.
What is the label on the binder, or type of documents inside? That can help you form a series and sub-series. You’ll label the tabs of the acid-free folders that you are going to buy with these titles. What about date ranges? That can help divide large series and sub-series physically into thinner folders. I use the left-hand side of my file for labeling the series, the center for labeling the sub-series, and the left for labeling the folder. Therefore: 300 Governance > 305.2 Directional & Mission Statements > 305.2.1 Correspondence. You want to at least list these all in outline form (inventory), so your researchers can find which box contains the folders they want.
House this all in an acid-free record boxes until you can revisit it later and decide what doesn’t need to be retained. Do any federal or state retention periods apply? If you can thin it out, relocate the documents to acid-free document cases. They are easier for both you and your researchers to handle.
Hope this helps!