Use almond oil (natural oil), easy to find in commerce.
Oil lightly the internal of the high part of the instrument in the following way:
Take the part from the lower insertion, hold it in horizontal and shed 3 or 4 drops of the oil, then incline it down in order to let the oil arrives in the midway of the bore.
At this point, introduce a suitable brush and turn it in a slow and uniform way, so the oil can settle all over in the inside surface mof the instrument.
This procedure is advisable to be done in the evening so you can let the instrument rest until the day after.
This procedure, if made in a constant way, hepl to preserves the wood; the inside of the instrument will always be clean and will facilitate the elimination of the condensation that appears when you play.

Very important: do not clean the mechanics and the wood with swabs soaked with chemical products because they will damage the silver plating. Use only appropriate swabs moistened of water.

ATTENTION:
It is warmly recommend to not play the instrument immediately when arrived, please wait 24-48 hours and leave it in the open case. This is necessary because the wood needs to get used to the climate after the transport and the change of temperature (that have to be around 20° C o 70° F Degrees) of the new place.