Maintenance

Unlike wood, ebonite doesn't crack from moisture changes, so you don’t need to worry about always disassembling the flute after playing. It is anyway a good idea to swab the bore every now and then, to avoid having residues from air condensation and dirt accumulating, which could eventually affect performance and intonation. 

Ebonite should not be kept under direct sunshine for a prolonged amount of time (eg: under a window, in a car etc, though it's generally ok to play outdoors in reasonable situations), this can cause the sulfur in the bond to come to the surface, making the flute change color to brown or even yellow in extreme cases. This can be seen in antique ebonite flutes that were not stored properly, though this is mostly cosmetic and they can still play just fine. It might make the material more brittle however, therefore less resistant to accidental drops and impacts.

For tonal reasons the stopper is made from a cylinder of hardwood, but because of the shape and lack of internal pressures it´s not in danger of cracking. Its surface however can get dirty so at least the headjoint should be swabbed sometimes, and like with any flute excessive condensation can affect performance during your playing session, so blow it out if you notice a non-ideal response.

The crown can be pulled out with a twisting motion, while the stopper can be pushed out (towards the crown exit) and repositioned with a rod of appropriate dimensions with a flat top. It is better to push slowly to avoid damaging the o-ring, though it can anyway be replaced easily if damage does occur. The stopper is generally placed about 19mm from the center of the embouchure hole, its position can be moved slightly in either direction which in some cases could benefit some players depending on the blowing approach, though this is generally not necessary.

The tenon joints are thread lapped. The thread will eventually compress, so to keep the flute airtight you´ll have to add more layers of thread, and if the material gets damaged from friction it can be replaced. Applying cork grease when needed will extend the life of the thread. You can use regular thin polyester thread, or even cotton thread (though it tends to get damaged faster).

Depending on the metal, the tuning slide will oxidise. To delay this you can keep the headjoint pushed all the way inside the barrel when you're not playing, to minimize contact of the slide with oxygen. The change of surface color is only cosmetic and does not affect the playing qualities, though if desired it can be cleaned with a silver polishing cloth. You can also use a small quantity of brass or silver polish product, but make sure to not let it touch the ebonite or it will dull the surface finish. Make sure that the slide and barrel tubes are clean before reassembling.

The metal tubes are attached to the headjoint and barrel with hot glue, excessive heat (eg: inside an unconditioned car parked in hot weather) can weaken the bond. A dirty tube can make the sliding action very hard, which in some cases can also put too much pressure on the glue and make it fail. If the tubes get detached from the ebonite, they can be glued back together by any local woodwind instrument technician, or you can try yourself if you´re crafty (at your own risk), make sure to avoid exposing ebonite to a direct flame and clean the slide from the extra glue.

The whole flute can be washed in cool water with mild soap if needed, don´t use abrasive materials and be especially delicate around the embouchure hole. Rubbing alcohol is better avoided as it makes the ebonite surface finish dull (though it´s otherwise safe).