Just leave it. I had one in are red house that sounded like they were eating the joists. What thematically doing was bringing the cellulose back to the nest and building. Saying that this one was huge (covered and area of 3m2) but nobody in the house got stung, I did not need to go in the loft, and when they had left it wasa great thing to go and look at, but I did take it out as it took up so much space.
It is still not as good as they guy in the New Forest who essentially let a hornet nest live in his spare room. The windows were all open and they just came in and built their nest. He just closed the door, taped up the gap and left them to it. They are fascinating creatures and try and find their nests to watch them (probably means I m strange as well).