lens – What is the cause of the stains on images taken with dust Nikkor AF-S DX 18-200mm ED VR II?

Dust or pollen inside this lens is a common problem. I've therefore finally removed the item before and I've cleaned it up, but even after this procedure, I have the same spots in a video as before. So, I guess it's the second very polluted element – but I'm not sure I can clean it up.
Someone mentioned that these items are covered, but I can not find any documentation / proof. The blower was not enough.

Can I clean it as a normal front element?

nikkor dust 18-200mm
visible spots on video


EDIT:
So, that's the dirty sensor. I put F22 and made the video with 18-200mm and 55-300mm and the spots are the same.

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