I have found the FireFly to be a great tool for sensor cleaning. Do you remember the StaticMaster brushes from the good old days of film? Aside from using the radioactive Polonium to ionize the surface and allow the dust to drop off it was great.
The firefly is the marriage of a Rocket blower ( with a microic replaceable dust filter) and an electric module powered by a replaceable 9V battery.
Air blown through the Rocket bulb is first filtered then super ionized after which you direct the stream into your cameras mirror box, sensor, lens elements, film... whatever. Dust falls right off.
Works well. Worth the $125.. but sadly does NOT remove oil spots.
You must mount your camera on a tripod as you must hold the power switch down whilst squeezing the blower. They could have added a switch... but probably did not want the thing accidentally left on to drain the battery