Have you ever had a student play a "B flat" when you asked him to play a "C flat?"
Or an "F sharp" instead of an "E sharp?"
Earlier this year I started making mini videos to help my online students (which is all of my students, at the moment) learn 5 note scales and root position triads for all of the keys.
The video series includes the enharmonic keys like F sharp/G flat. I ended up making 7 1-minute videos for the names of all the keys, including all of the black keys. No musical staff here. That comes later. People learn the names of their friends before they learn to spell them. Right?
The 7 minute mini course is free and you can find it here: