Aw man... some stubborn dust or maybe a damaged sensor cover? V1

There is either a small piece of dust or some other damage on the sensor that cannot be easily removed. Didn't really notice it until today. I used a Giottos Rocket Air Blaster with no effect. Then I got out the cleaning pen. No luck either. I might have to get a bit more aggressive with the cleaning to see if I can remove it. I shot this image at f/8 and it showed it's ugly head. Might be hard to see on screen, but it is really evident when post processing the image.

Any suggestions for cleaning that you can recommend?

Dust located in upper right corner in band