Hi Dez,
quite recently I cleaned up an older Hohner Cassotto 26.
It was in good condition but with a musty smell and with squeaky and clunky keys.
I disassembled it and bathed all parts a few minutes in warm water with some dish liquid. After that I rinsed it with pure warm water and led all parts dried over night.
After that I lubricate the valve shafts with a bit Vaseline and reassembled the instrument.
After that it nearly feels like new, no squeaky and much less clunky keys, also the smell is nearly gone.
Greetz
Michael
