Wooden flutes are completely different than modern metal flutes, and should be treated as such. They can react quite rapidly to temperature and humidity changes, so they must be gradually broken in when purchased new (or when they haven’t been played for a long time), and regularly oiled.
When you first purchase your new flute or start playing again after a hiatus, the flute must be played in slowly. Most makers recommend no more than ten to twenty minutes a day for the first week, then steadily increasing to an hour a day, then adding an extra half hour a day until you reach the amount of time you want to practice daily.
It’s vital to maintain relatively stable temperature and humidity. A cold flute should never be played immediately, but rather gradually warmed before practice or performance. Low humidity environments (think air conditioning, central heating, air planes, dry winter weather) are especially detrimental. An orange peel in the case, and humidifiers or even a bowl of water in a dry room can help to combat cracking that can occur in low humidity.
It is essential that you regularly oil your flute. Each flute is different, so you must be in tune to your particular flute’s needs in terms of moisture—as you progress, you’ll be able to tell when your instrument is dry, but a good indicator of a dry instrument is a white tint to the bore. Many different kinds of oils can be used, but the maker of your flute should be able to recommend what they feel suites your flute best, and some makers, like Martin Wenner, sell oil blends. Apply a small amount of oil inside and out with a cloth (not your usual cleaning cloth), and leave it on a flute stand overnight. Then, prior to playing the next day, wipe off the excess oil. It is imperative that you don’t get any oil on the D♯ key, as this will cause stickiness which is difficult to remedy.
Always be sure to swab the moisture out of your flute during rehearsal breaks and before putting it away.