Mickey2

I use Auto Glym, it's good, but mostly because it's easy to buy here. If Cari's suggestion is easy for you to find, go for it. I use two main types; both resin type; one is whitish and have a certain amout of very finely milled grit that polishes the surface when it's applied. I have used it on almost anything with good result, including back cast iron machines with gold decals. However, the glaze (some brands call it sealer) which Cari mentions is the same stuff with out the grit. The grit has a microlevel abrasive action.

The clear no-grit stuff is probably better for vintage machines in the long run. Some glazes are suppose to last for years once applied, but it's as a second step after the basic polish. This is generally how it's recommended for cars and so far I haven't seen any adverse effect. It depens though, if you are very carefull with this machine I suspect a conservator would use a pure mineral based wax, like Renaissance Wax. I use my machines regularly, and I think the resin type polish is gentle enough to use and it gives a much more lasting protective layer than most waxes.