Season 1, Episode 7 of Better Call Saul (“Bingo”). Not necessarily really a spoiler but just to err on the side of caution, spoiler-boxed:
Mike spritzes a stack of cash with some unknown, apparently invisible liquid, which is driven on an RC car to the house of someone who is known to be keeping a big stockpile of cash somewhere in his house. The guy picks up the cash and takes it inside, and Mike later breaks in to the house wielding a purple light (I assume UV), which he is able to use to find a trail of fingerprints leading him to the cash stockpile.
So what chemical would realistically fit this scene? It would have to be visible only under UV light (obviously), but also able to transfer from paper money to one’s hands very easily and leave a noticeable trail on anything subsequently touched. Also, how long would such a trail last?
*I did do a search and found the thread where this episode was discussed in CS. I only skimmed it and saw a couple people mention the scene but not what chemical it would have been.