I recently visited southern Arizona and bought a 6 hole Navajo Flute while there.
After playing with it for a week, I decided to oil it. The pamphlet I got with it said to oil it with olive oil or woodwind oil. I poured a small amount in and spun the flute around to coat everything.It took a bit to get everything oiled, but I did notice a difference in the sound afterwards. The lows were easier to sustain and the higher notes were more clear.
I looked around for a simple scale and there were lots of different versions that didn’t contain all the notes I was expecting. Here is my revised scale for my flute.