I am wondering what to apply to the fretboards of my guitars.

There are commercial products like Finger Ease (messy spray) and Fast Fret (expensive) that make fretboards and strings easier for fingers to negotiate. I have read that many people use mineral oil or furniture polish instead. I am wondering what the best solution is. I like Fast Fret, but it seems a little weak, and you have to apply it every day.

I was thinking of getting a bottle of mineral oil and adding some orange or lemon oil to make it smell good. I also wondered about coconut oil, since it's a little heavier.

The last guy who worked on my guitars said I should use lighter fluid to clean them, but right now I'm only interested in making them less aggravating to play.