Well then, since we're sharing "experiences" with the demons:
There was a family in our congregation that was always having problems (their name was Potter...no, no--not of the Harry Potter class LOL). Anyway, the elders were over at their place so many times, and yet the spiritual counsel didn't seem to help, and finally (I forget the details), it was "determined" that they lived in a demonized house. They sold the house, and after renting locally, the problems continued. Eventually they moved away--problem solved.
And then, there was the locally infamous (or, at least it was when I was still in the loop) story of Matt Chojnacki, a big ol' barrel chested Czeck elder. He was studying with some folks who were having "odd" problems. One day his wife was walking down the hallway in their house, and felt a 'very cold breeze' coming from an antique mirror on the wall. Guessing that this 'demon-mirror' was the source of the problem, Matt suggested that the folks let him take it out to the back yard and break it. They agreed, and so he did (or attempted to so do); but here's this big guy (and I mean he was big), with a sledge hammer, trying with all his might to break this mirror, and the hammer-head just bounces off. Then he says a prayer to Jehovah, and with a final blow the mirror just blows to smithereens. [That's how I remember the story: Both Matt and Anita (his wife), are now dead, and their son was on my last df'ing committee, so I daresay no corroborating testimony will ever be forthcoming].
It seems to me, though, that such stories as this have found less popularity with JWs over the last 30 years, and I couldn't find any overt statements in the WT since about the mid-60s, other than the Biblical references to such. Perhaps others here have more definitive info?