Even if you dunk a typewriter in cleaning solvent over several days, you're not going to get ALL the gunk and grit out of it.  In my mind, in order to get a typewriter to that Nirvana of being able to work well dry, you would have to tear EVERYTHING down to the frame, and practically polish every nut, bolt, gear, and just about every other part associated with that machine.  Then you would have to put it all back together according to OEM specifications.  And not many collectors are qualified to do that, even me.  I have a 1956 Underwood that was badly rusted from poor storage.  I took it home, tore it down to about 50%, soaked it in diesel (which is a thin cleaning solvent as well as a fuel), for two days.  I bought another Underwood from an antique store for parts, which I used about 40-45% of it--rollers (all 6) rails (both), type bars (all), segment slots, tab stop rack, margin mechanism (the entire thing), ribbon spool covers (both), and out of a '55 Underwood, I pulled out a shifting equalizer bar.  It took me four or five days to put this machine back together where it worked halfway decently.  And even then, I wasn't able to get ALL the dirt hiding in all the tiny crevices, nooks, and crannies.  Got alot out, but not all. 
I do realize that too much oil will hurt a typewriter, and I am very sparing with it.  But the machines I have worked with dry always turned out to be a little stiff for me.