How to clean out black grime, inside AirSense 10's unopenable motor chamber?

[StackExchange]

Compressed air, hair dryer, vacuum cleaner couldn't remove this black grit off the side glass, or blades. Toothpicks, cotton swabs couldn't reach the sides.


How else can I clear away, and wipe out, this black grime?

As this motor works fine,  I don't want to waste $200 USD on a new motor. I don't know what this black smut is. I don't burn or smoke anything. Whole-house central HEPA is installed into my home's HVAC. 

[Nightynite]

I wasn’t very successful either although mine didn’t look that dirty. Mine made a noise as I went ahead and replaced it. As far as cleaning it, the only other thing I thought doing but never tried it was to get some of that automotive electronic cleaner that is used for cleaning the mass air flow sensor. It’s aerosol, it’s made for electrical, it has a straw for getting in tight places.
I would probably blow it out real good and even let it soak in a jar of that stuff, and then blow it out with some compressed air and let dry some more.

You can buy it at any automotive store.