No, I'm not actually going to tell you that I found some fingerprints from a ghost! But I do want to talk about some faint ways of noticing when a dead person has paid a visit.
In the last 24 hours, I was hit by an unfamiliar mood at three different times. Each time, the mood was present for a few minutes before I twigged that there was something odd about it (the mood was untriggered and irrelevant to what else was happening, as far as I could tell). The mood was heavy-going, and as soon as I paid attention to it, I started to get an impression of a senior male.
On the third occasion, I tuned in more carefully, thinking that this ghost must be trying to communicate. This is when my mind can start making things up while it strains for information. I try to stay mentally silent, and only pay attention to images which are slow to form, and which linger even when my mind starts wandering over the top of the image. This time I just had an image of a key, and it wouldn't go away until I had drawn it on a piece of paper. I don't know what it was about. Perhaps there is another instalment to come, or maybe the ghost just wanted the satisfaction of knowing it could be heard. Often entities start to shift when someone acknowledges them. I think that acknowledgement helps the entity or ghost to get a grip on their own identity, and then they can reflect on their own situation, with a possibility of moving on.