If blower cleaning and the camera’s built-in cleaning don’t remove the spots, they may need a proper wet sensor-cleaning process rather than more blowing.

A sensor can be cleaned with a sensor swab, but it should be done only with the correct tools, cleaning fluid, and careful technique in a clean environment. It’s not something to improvise, and if you’re anxious about damaging the sensor, that’s a good sign to be cautious.

Best advice: either learn the dedicated process thoroughly from several reputable sensor-cleaning tutorials before attempting it, or send the camera to a service department. Don’t rely on a single video or random method. The key is using the right methodology and materials, not just touching the sensor lightly.