I remember seeing an old 1940's B&W movie when I was a kid about a house that was supposedly haunted.
All I remember was that there was a group of people in the house and a lot of comically creepy things going on. It turned out to be someone trying to scare everyone away from the house for some underhanded reason (a very typical haunted house plot).
I'm pretty sure this was a comedy.
The thing that I am positively sure of is that at the very end of the movie when the bad guy has finally scared everybody away and is satisfied, he suddenly sees objects moving by themselves; and since he knows it wasn't his doing, he also flees the house. Just before "The End" comes on the screen, we see two real ghosts materialize and begin waving goodbye to us (the viewers).