Phil has a fantastic and very detailed page on his restoration of one of these. The link is
http://antiqueradio.org/rca16.htm and this will give you a good idea on how to do one of these. Since they are very tight as far as getting to everything you will need plenty of patience but Phil proves these can be done faily easily one you figure how to expand the rails out to get to everything. You might be able to get the corrosion off the tuner with the one type of Deoxit made for brass and gold contacts. I have two of these. One with pedistal and one without. I love mine.
-Tony