It's amazing how much stuff gets in there, I started a thread here once myself on the subject! Some casters do seem better/worse about collecting but the amount of thread I have, they all get it.
I've started chair cleaning along with battery changing along with Daylight Savings Time. I put it with it's wheels up in the air and using my craft scissors and seam rippers and all sorts of things, mostly just cut my way through and pull out smaller parts.
It seems pretty silly, but since my friend gifted me with a modern Bernina with a thread cutter, that has made a tremendous difference in how thread covered both my house and my self are nowadays! So many things have changed, it turned out what I didn't like about partial seam construction wasn't the stopping and starting, but those darn 6-8" tails of thread from my vintage machine.