The machine was clearly well-used, with wear to the finish from fabric and hands sliding over the surfaces. After use, the machine must have been stored away for perhaps decades, judging from the dust, dirt and 'tiredness' of the wooden case.
The wooden carrying case for the machine is similar to typewriter cases in that it consists of a base and a lid. Very different is the domed, steamed 'bentwood' and the lacquered finish. With the gold decal the case looks more like early Hammond cases.
The general 'tired' look of the case with the varnish being broken in spots could be revived very nicely with furniture wax. There may be other and better methods, but this will fill the bare spots and protect the wood and create a more even finish. Working carefully around the decal, not taking any chances with rubbing or solvents from the wax-preparation damaging it. As can be seen in the image with the corner waxed, it brings out the depth of the wood again.
The metalwork of the machine had some superficial rust as well as general grime. After cleaning with a damp cloth, a basic, quick polish with a little bit of Brasso brings out the shine again. An important part to clean and make smooth again is the thread-tensioner (or so I have gathered from the vast array of resources online about these machines).
That's the complex looking spring-assembly with knurled nut on the side of the machine head. The two dished discs in that stack pinch the thread to create tension during sewing. These fortunately cleaned up well and are here again assembled.
The damage to the decals and paintwork of the machine can be seen very clearly here. The cast frame of these machines was painted (dipped) in black lacquer, then decals and then followed by a clear-coat of shellac.
The clear shellac has been worn away on most of the machine - the spotty, brownish layer on the bed are probably remains of this protective shellac coating. We'll have to see how to tackle this.
Maybe this will be left as-is; it is a well-used machine and will be permitted to look it. Getting it to work again is the main thing (it's being eyed by a daughter, keen on using it).
Very different mechanical technology again, very neat to tinker with and fix-up :-)