Warranties and Manuals can quickly accumulate to overwhelming proportions.  Here are a couple of storage options:

1.    Buy a set of alphabetical index dividers and a fairly large binder.  In each alpha section place a few page protectors.  Insert manuals into the page protectors in the appropriate sections.   E.g. Stereo in the "S" section.  It is quick and easy to access the manual you need when you need it.  Label the spine of the binder as to the contents and store it on your bookshelf.

2.    Place each individual manual in a page protector and find a creative way to store each one in the room where the item is located.

Whatever storage system you use, remember to go through the manuals from time to time and weed out the ones that you no longer need.