@lawnor, re. compressor I rather meant a screw you have at the bottom of the tank, I can’t described it any better, so I took picture of what I have.
Important note: before you unscrew it let all the air out using safety valve or the one your moist trap, also do it over some container and have paper towel ready. Hope this helps.
Regarding seals I meant those around your air valve, deep inside the brush. Your cleaner may clean it properly, but the valve works whole time you airbrush and may add some lube every time you push your trigger (lubricant should never be removed completly by ultrasonic cleaner). On the other hand now that I think about it, I don’t think there is enough of oil there to give you such headache. Anyway a useful video on airbrush servicing:
