To clean the bright metal pieces on my Davis VF I used Bar Keepers Friend, which removed all the oxidation and rust spots. It has a little bit of a mild acid in it that cuts through all the gunk.
To clean the body, I used Dawn dishwashing liquid on cotton balls, then rinsed that and tons of gunk off using just wet rags, dried it, then used sewing machine oil, which removed still more gunk. Mine is down to bare metal in some spots and has virtually no decals/decorative paint left, so I didn't have that worry. Just had to be careful not to do any further damage to the finish. The black finish is the "Japan" that was mentioned earlier.
Dakotamaid, could you please tell us the Serial Number and the city, which is stamped on the front shuttle cover slide plate. There is a group on Yahoo.com called Davis VF, and they are collecting the serial numbers trying to get some good dates established. Davis SM Co. didn't keep any records that could be found, so there's no way to date the machines for sure. Charlee's VF and my VF are within a very few thousand of each other, and hers says Watertown, NY and mine says Dayton, OH, so we know hers was 1889 and mine was 1890. They moved to Dayton OH early in 1890. That's as close as we can get without paperwork with them.