After each use, wipe your manual sander with a dry cloth to remove any dust or dirt that may have built up.
A drop of light oil on any threaded and moving parts will keep the sander in tip-top condition for longer.
Storage
When your manual sander is not in use, store it in a dry and safe place.
Leave an old piece of sandpaper attached to the sander to help protect the foam underneath. Do not store anything on top of the foam or you may end up with an indentation or less than perfectly flat base.