Jody - Your machine is really pretty and should clean up very nicely. Interesting bobbin winder.
All you need to clean the decals is a dab of machine oil on cotton wool or a soft cotton cloth, then rub it dry again with fresh cotton wool or a cloth. You won't silver the decals with machine oil. The residue of oil on the presser bar and foot will come off easily with Peek metal polish. You will find all the information you need about cleaning vintage machines and using long bobbin machines in my Youtube videos and on the blog - links are below. On the blog you will find a link for the metal polish.
Nancy - the tension discs need to come off so you can reposition the thumb tab. If I could stick my hands into the computer I would do it from here.
Needlebar isn't difficult to join. They get irritated if people want values of machines or just go in for a bit of information but make no real contribution. It's worth joining just to get access to the picture gallery.