The approach I used is proposed (without warranty) by Nicholas R for CCD/CMOS Cleaning. Nicholas provided detailed, step-by-step directions, but they are no longer posted.
I ordered his swab (others are available via the web). I already had Pec Pads. I used PEC-12 (a cleaning fluid) bought at a local camera store as the stuff cannot be shipped by mail). It worked. I am happy. But like Nicholas R., I offer no warranty!
One comment: Nicholas does not state how to lock up the mirror, as that is camera-dependant. Use your camera manual. Generally the recommendation is to have the camera power supply plugged in during cleaning, but if the power fails you are hosed. I suggest instead a freshly charged battery and usingh battery power.
Addendum 1: There is still a website explaining how to clean digital camera sensors. I have not tried it, and cannot speak for it, although It was recommended by Tim Gray who runs the DDQ newsletter.
Addendum 2: many newer digital cameras have a self-cleaning feature which works reasonably well.
For the example, I had three spots on the Canon sensor that I managed to clean off. Here are two photos showing before and after cleaning (the cloud difference is due to different times of taking the images):