Glad you are liking your resin recorder.
The secret to high C# on all recorders (and especially necessary with the Bernolin) is a gentle attack – i.e. tongue it very lightly, but with a good amount of breath pressure. It can be tricky. Sometimes it seems to improve as the recorder warms up from playing. I’m assuming that you warm the head joint beforehand, of course. You MUST do this, with any recorder!! I put mine under my armpit. I know some people recommend warming it for up to 15 minutes. I don’t do that usually, but certainly 5-7 minutes, with the area of the windway tucked into my armpit (yes, I have a shirt on – yuck, otherwise!!).
If you are coming into the C# from below in a stepwise fashion (e.g. with a Bb, B, C or whatever), you can try gently slurring that note into the C#. This definitely makes it speak more easily.
As far as maintenance, with most plastic recorders I do not take them apart and swab them out after playing, because the joints of regular plastic recorders can become loose over time as you assemble and disassemble them over and over. Once the joints get loose, you pretty much have to throw them away.
But with the Bernolin, I take it apart after every session and swab it out with one of those plastic sticks with a small cloth in it. I take it apart because I’ve been told that with threaded joints, the thread itself can get wet from playing (although I’ve never detected this), and you want to air that area out and let it dry. You also don’t want the thread to flatten down from always being assembled. Also, there’s no worry about the joints becoming loose because that’s what the thread is for – you can replace (although I have yet to have to in the year that I’ve had my Bernolin).
So, good luck with it!
