Manual or electric? I smashed apart a last generation Smith Corona word processor once, separated out the few boards and wire, transformer, teeny tiny drive motors, not much there but worth the time to hit with sledge and smack it all apart. Some 1970s era electric typewriters have a decent transformer, which I scrap here as electric motor, some of the IBMs and older SC have ali shells as you found. Manual typewriter I have scrapped seemed to be all ferrous, just tossed in shred.
Be on lookout for old monster IBM Selectric Composer, which looks like a typewriter but is actually a compact electronic typesetting machine. Loaded with old electronics and whatnot. photo here. (edit: added this...) NOT to be confused with Selectric Typewriter. How to tell the difference? when you lift one, you know. Not usually found in homes, but I did haul one out once.
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