Alas poor Whopraysforthedevil, Where be your gibes now? your gambols? your songs? your flashes of merriment, that were wont to set the magazine on a roar? Not one now, to make reply first with a Shakespeare joke? quite sorrowfully delayed?
I mean the Valar tried to rehabilitate Morgoth but banished him beyond the doors of night in the end anyway. I also don't think that's what happened to Saruman and Sauron. Their souls were diminished and left formless forever, but not banished like Morgoth. Pretty sure the only being completely removed from Arda until the breaking was Morgoth.