We recommend talking to a couple of past co-workers, family members, or friends to get their thoughts about what sets you apart. Their feedback will give you great insight about what makes you unique! We all have that one thing, and now is the time to share yours! They may tell you it is how encouraging you are, how hardworking you are, how well you interact with others, or how dependable you are. Your uniqueness will set you apart from all of the other people helping you land the job!
What is a janitorial duty you have only had to do 1 or 2 times because it was outside of the norm? This is the answer to the second part of the question. It is a unique duty you have performed that is not normal for most janitors. Having these unique experiences makes you more hireable!