I own 2 Year Old Nikon D600 (Problem child at staining, dust, oil, etc.).
The camera I have 8 months to Nikon returned to be converted to the closure (free, because class action in the US).
Have until recently, had no problem (I photograph mostly of Aperture 1.4 to 10) but as I did last week macros Ohh Schreck, many spots were visible (top-left).
Today I got the Sticky sensor stick and tried the same. In 2 passes all stains were gone. ALL.
Have at aperture 32, a safety test done and the sensor was super clean, absolutely free from dust and oil.
For 30EUR I would recommend this product only. Pay securely for several years to make do with the 10 adhesive sheets.