I recommend applying a natural beeswax or carnauba pastewax to your flute every couple of years, or when the finish starts to lose its lustre. Below are some general maintenance tips.
As you blow into your flute, moisture from your breath condenses to form water droplets that collect on the inside of the slow air chamber, the flue, and the bottom of the fetish. It is important to let this moisture dry up after each playing session; if let to sit, mold can develop on the inside of the flute. This is especially true if playing a flute that has not had the slow air chamber coated and sealed with some type of finish. After each playing session, remove the fetish, point the blow hole towards the floor, and give the flute a few vigorous shakes to remove any water droplets. If you own a particularly delicate flute, remove the fetish and forcefully blow air through the blow hole to remove the water buildup in the slow air chamber. Use a cloth to soak up any water that remains in the flue and on the bottom of the fetish. If the fetish and the flue haven’t been finished with a sealer, keep the fetish off the flute long enough for any absorbed moisture to evaporate.
If you are outside on a cold day and want to play, place your flute somewhere warm, such as under your arm, bringing the temperature of it closer to the temperature of your breath. Do not store your flute for long periods of time in direct sunlight or in extremely hot conditions, such as the dashboard of your car on a hot and sunny day.
Dents and scratches:
It is important to store you flute in a safe place. In general, dents and scratches will not affect the way your Native American flute plays, however, they can become a problem when they are located around the nest/flue or the finger holes. Damage to a finger hole can change the pitch of the note that is produced by that hole, or it could make it difficult to properly cover a hole. If the nest becomes damaged in a way that allows air to leak from the flue, or the geometry of the flue/sound mechanism is damaged, even slightly, the tonal quality of the flute could be greatly affected.