If you're using DNLR camera then without any damage and reducing its quality of pictures taking you can clean dust on "Image Sensor" with Camera blower. In most of the cameras "Ultrasonic sensor cleaning" systems available but that is not much effective in this regard. If maximum dust appeared then you've to use "Handled Air Blower". These blowers are not much costly available in market with cheaper rates starting from 3$.
Note: Don't Clean DNLR Cameras with cloth, your sensor may be damaged and quality may reduce.
Without reducing quality of pictures