Do you have things which were used by older members of your family in days gone by which you still use on a regular basis? I got to thinking about this and found more than I thought.
The photo below, from about 1931, shows my Dad (twice!) using a bookrest which appears to have a paperback book on it. It would have been taken on the Kodak Box Brownie by my mum and somehow appears twice. I don't have the knowledge to be able to disappear the 'ghost' image, even if it can be done.
What do you have???