Dirty image sensor - PENTAX K100D

[dfed]

I could not find a better place in the forum and therefore I write here:
I use Pentax K100D, kit lens (18-55).

In the last few weeks I notice some dots, which can be seen in the pictures below:

1/750 - f8.0

1/90 - f22.0

1/250 - f13

I tried to clean them a few times with the product below with no luck:

I have tried other lenses and it's still the same. Could you help with advise how to sort this out?

 

[The_Traveler]

Camera repair shop for sensor cleaning

 

[Vtec44]

Can the lens itself cause this? I'd try another lens just for the heck of it.

 

[Garbz]

Can the lens itself cause this?

No that's sensor dust. By the way you labelled the above apertures backwards.

 

[Drake]

By the way you labelled the above apertures backwards.

Exactly, I was wondering why the dust is mostly visible at f8.

I wouldn't try too hard cleaning it. If you can't get a rid of it easily, get it done by a professional.