I don't want the chest of potions to become a loose end, a "plot hole" that leaves the reader dissatisfied. It has always been my intention to make them useful later on, but I haven't figured out how yet.
Now, this morning I read an e-mail from Ron in which he describes his intriguing plotline for his novel. He referred to the MacGuffin I had heard this term but wasn't familiar enough with it to truly understand what he meant by it. This called for Online Research. Now, with a new understanding of the MacGuffin, as well as other terms such as Chekhov's Gun, I am mulling over how to solve the potion problem.
The potions in my novel are NOT the MacGuffin ("a plot element that catches the viewers' attention or drives the plot of a work of fiction.": Princeton University, Wordnet 3.0; from wikipedia) If anything, that term could be applied to Kyer's medallion, and maybe even to Kyer herself. I think the chest of potions is Chekhov's Gun, which refers to an object which appears early on, but whose purpose is not clear until later. Without even knowing this term I've always believed that if there's an item on stage that draws my attention, the characters had better use it at some point, or it's just a distraction. And that's annoying. That is where the term Chekhov's Gun comes from (Anton Chekhov, who insisted that if a loaded gun is on stage a character had better try to shoot somebody with it eventually).
In order to not leave the reader hanging with regards to the potions, I need to clarify (for myself at this point) how they will be used later. I don't write with an outline, I make stuff up as I go. Somehow, labelling the potions as a particular plot element has helped me to focus on what I need to do to avoid a terrible plot hole problem.