For best results just use Photographic Solutions cleaning supplies for DIY cleaning. First try using the HEPA Orbit blower then gently swipe on the sensor using the Sensor Swabs with the eclipse solution. Thats the best combo that I have been using. Links below
https://photosol.com/...
Had the same problem before with my images. What I did was simply clean the sensor myself using Photographic Solutions Sensor Swabs. Gets the job done.