Water dropping out.
(explanations to the tweet of mai 2nd 2015)
Everybody knows that the water in the flute can't be crystal clear.
We talk about condensation water and no saliva, sure. So the water inside of the flute which drop out after playing a while, is not direct body fluid, of course, but the assemblage of moist in your breath, which gets condensate by touching the tube and/or the temperature gap with whatever...
When I was little, my teachers told me to keep this residue where it is, inside the mouthpiece and never clean it, because they believed that this deposit shapes the sound. But that was at a time when flutes were not laser cut, and when the skill of the flutist was primordial to compensate the weakness of the instrument itself.
Nowadays the flutes are quite perfect at purchase date. I do not really believe in talks like "the sound will be made later" or "you got it tamed". Of course, since the metal (silver, gold, or palladium/platinum) is very thin at the sweet-spot (cf golf-player-terms) and we blow repeatedly on the same place, it might move slightly.
NOTE : So, when you choose a new flute, don’t buy one in the hope that it WILL get better, but WHICH SUITS YOU IMMEDIATELY. (Of course, you will have 2 major criteria for it, 1) who you actually are : your immediate style, and 2) who you might become in the near future, if you are still developing yourself..; >> this could become a good subject for a new post o_O ... noted ! )
Anyway, this is a very good reason to tell again to NOT PUSH NOR SQUEEZE THIS VERY AREA AT ALL in any case, so swab your cotton bud VERY GENTLY and, still not too often, once every 2-3 month is fine (except if you have the bad habit to eat immediately before playing, without brushing your teeth… :$)
Why the alcool? It dissolves grease and evaporates quickly. Since the flute is often made in precious metal, alcool does no harm to it. NO ALCOOL FOR WOODEN HEADJOINTS. Never.
You have chosen a good flute for you. You love your flute. So keep it that way by taking care of.