1. Spots on your digital photos, usually visible in skies, mean dust has settled on your camera's CMOS or CCD sensor, the light-sensitive chip surface that replaces film in modern digital cameras.
2. Start by blowing as much grit as possible off the rear lens element using a squeeze bulb or canned air. Then use a lens brush, or soft camel hair art paintbrush, to remove more stubborn particles.
3. Once you've removed scratchy grit and dust, moisten a microfiber lens cloth with special lens cleaner solution, usually ultra-pure alcohol.
4. Wipe the moistened microfiber gently around the lens elements. Examine lens elements in full sunlight and repeat until they're smudge-free.
5. Then blow out the camera's interior with a squeeze bulb or canned air. Hold the can vertically so liquid won't squirt out. For SLRs, concentrate on the mirror and focusing screen atop the compartment. Shake any loose particles out of the compartment.
6. For SLRs, set the camera's shutter speed on "bulb" (meaning you have to hold down the shutter button) or mirror lock-up settings (check your camera's manual). Lock the mirror up. Closing the mirror on fingers or swabs can damage it.
7. Use a blower bulb or canned air to blow grit off the exposed sensor. Carefully hold the can vertically to avoid spraying liquid propellant.
8. Pre-moisten the sensor swab pad with two to four drops of sensor cleaning solution.
9. Gently wipe the paddle the long way across the CCD or CMOS sensor, making a single, full-length swipe. Turn the paddle over, re-wet if necessary, and repeat the process. Do not use each swab more than two passes, changing side with each.
10. Close the mirror and replace the lens. To prevent or minimize repeats, see backpacker.com/cameracare for more on keeping your cameras clean.
11. For more info watch the instructional video at photosol.com. If you're not up for the task, send your camera in to the manufacturer for professional cleaning.