A 19thC Cornish house in Lanyon had a sealed room to imprison a ghost.

Lanyon (pronounced 'Lanine') House, in Gwinear, also had its sealed chamber [to imprison a ghost]. On one occasion two maidservants, out of curiosity, took up some of the floor boards in the room above and let down a candle on a string. For some unexplained reason the haunted room was seen to be half–full of feathers, which must have at least provided a comfortable resting–place for the rats, whatever the spirit may have thought about it.

I suspect that birds got in through a broken window and that accounts for the feathers. Still, the feathers and the rats are just sidenotes to the belief that one could seal a ghost in a room