Cleaning Resistant Sensor Dust
Sometimes, conventional sensor cleaning is just not enough, especially on older cameras that have mostly never been cleaned or don't have the piezzo anti dust thing.
In those situations when dry and wet conventionnal cleaning is not enough, I use the electrical tape method.
It requires electrical tape that doesn't stick well. Most of the time, the cheapest one does the job: I just make sure there is almost no adhesive on the sticky side. I don't want a strong adhesive that will rip out the sensor, or a bad adhesive that will leave some nasty residue.
I think it works in two ways: those tapes are very static: they tend to attract dust naturally, and the adhesive finishes the job.
After conventionnal cleaning, I use a piece of cardboard and the electrician tape the catch all the remaining dust. I do it with one little piece of tape: take a test photo, check the remaining dust, and repeat.
I don't try to get rid of 100% of it, if I reach a dozen spots, I'm good.
Do I recommend you to do it? nope. I don't recommend anything. But feel free to try it on an old sensor.