This mistake could damage your camera and ruin your photos.
If you often swap lenses on your camera, it's almost inevitable that some debris will end up on the internal sensor. It's not the end of the world, so long as it's not something abrasive like metal shavings or grains of sand. Whether you spot the speck of dust on the sensor after reviewing photos or cleaning your camera, it's important you resist the urge to dislodge the dirt by blowing directly onto the exposed sensor with your mouth. If you do, you might end up introducing a bunch of moisture into the element via your spit.
Your spit can turn into hard-to-remove stains on the sensor that show up in all your photos, making the problem you started with worse. You may even have to seek professional help to get it cleaned, unless you have the know-how to do a wet-clean using a dedicated cleaning solution. Instead, here's a better approach to cleaning your camera sensor that doesn't involve your mouth.
To start, it's a much better idea to use the built-in sensor cleaning feature that most modern cameras offer.
