Originally posted by joerotheray I bought a Pentax K70 to replace my stolen K500. Both units when new showed small specs/smears on the censors. Ultimately I decided that they were in fact manufacturers oil smears, minuscule as they were. I exposed the censors on each occasion and stroked ever so gently with a previously well examined earbud on the surface of the censor that I had to ask myself whether I had touched at all. I was lucky, it worked both times.
I previously dabbed with a clean, dry earbud at dusts to remove them, no stroking on my part. This did a decent enough job but eventually I purchased a VSGO APS-C cleaning kit with the solution at 12 swabs. 2 swabs later and everything is absolutely pristine again*. From what I've heard, the ultrasonic dust cleaning of the K3ii/KP/K-1 etc. is vastly superior to the sensor wobble we K-70's get. Such is life!
*Until the other day where I noticed a dust-spot, light, directed blow with an air blower, whilst holding the camera face-down did the trick nicely. Everything absolutely immaculate again. Would wholeheartedly recommend the VSGO kit if [you] are steady-handed. It's worth mentioning that I'm hugely OCD about these sorts of things. My OH loves when I clean because I'll spend an entire day on it and everything will be truly spotless.
---------- Post added 11-20-19 at 07:00 AM ----------
I'm wondering also whether the OP means dust on the mirror and therefore visible through the viewfinder, or on the viewfinder itself. I assumed the sensor wasn't easily removable, given their statement about removing the screen.