Were the Nazgul free from Sauron for the most part of the Third Age?

[Gordis]

Originally Posted by Udukhaturz

Gordis, just a stab in the dark - "No other blade, not though mightier hands had wielded it, would have dealt that foe a wound so bitter, cleaving the undead flesh, breaking the spell that knit his unseen sinews to his will." - The Battle of Pelennor Fields, Return of the King, p.120

Obviouly the spell had been undone and the Witch-king's body was subject to harm. As to what happened to his body, I will posit this: as so happens in legends/literature, his body crumpled to dust, like Saruman's, when Eowyn gave him the death blow in the skull.

Some spll was undone, sure. But I always read it more literally: the spell that knit his body to his will, i.e. he lost control over his body and fell to his knees. Anyone would do that with his knee ligaments damaged. And that gave Eowyn an opening she could never dream to have.
But I know: it is just conjecture. Your way to interpret it is as good as mine .

Originally Posted by Udukhaturz

That is a possibility, but I was always under the impression that the Lingerers, if they wished, could become visible, if only to the mind. There is a quote on this but I don't have the time right now to look for it. Maybe someone else can look for it.

Couldn't find the quote, though I believe I know it. Yes, they could communicate with the living- ?by Osanwe kenta?, but hardly they could become visible.