You have complimented the dust with some saliva, bacterias and other organic material. Together with the airborne fungus spores a perfect breeding ground for fungus. Congrats
Jokes aside: your mouth is the very last thing you want to use. Now the advice with the blower is of no help anymore. Be more careful with the cleaning set. If in doubt then stop and read.
I'll get the swaps and see how I go. Am I suppose to position the mechanism inside to reach the sensor or is that mirror thing it? Can I clean that as well?
OK I just found out a mirror lockup feature on my D50 which I think moves the mirror aside to expose the sensor, now I can see it. Its a good start.
If all else fails then I'll send it to the expert, have never had the camera serviced before so might be a good thing. I'd also like to clear up some hot pixels that I've noticed in my night shots.