Sewing machines and Typewriters

We are recently moved and the previous owners left some stuff behind. How do I clean these and find information about them? I don't want to damage them more. The 2 sewing machines (both are Singers) are in the basement where they were when we moved in and the typewriter (also a singer) was up in the attic along with a Royal typewriter. Any help and/or info would be greatly appreciated. Thanks