ok, how do I clean this?

Well, I had some minor dust on my ToUcam chip that should have been no big deal except for the fact that it is right smack on the center. So I blew it with an air bulb, did not work. Then I dipped high purity HPLC-grade acetone with a cotton swab. The spot was gone but surprise surprise a gazillion things were left because I used the cotton swab. So back to the air bulb, but now I have 4 dust particles left.

What is the best way to remove this dust? How do the manufacturers do it commercially?

Thanks,
Ivan