I've successfully managed to get the menthol smell from some menthol
juice out of a plastic dropper bottle by washing it in dish soap several times, then soaking it in plain water for a couple of weeks while I was out of town. It still had the faint odor of menthol, but after I filled it with another
juice (no, I couldn't smell/taste it in the juice), and used that juice up, it was gone entirely.
I don't know if this helps you or not.
What brand of mint are you talking about? I've been looking for a better bottle for dripping than the ePump (Johnson Creek).