The methods for cleaning any optical device like DSLR Lens or compact digicam is the same. These methods can be adopted to clean effectively any such optical device which has lenses.
Prevention is better than cure:
Following are the most effective preventive ways to keep the camera lens clean:
1 – Ultraviolet (UV) Filters:
Ultraviolet filters are the filters which are attached over the actual lenses giving adequate cover to them from dirt and impact. It is one of the economical ways to protect the lenses which reduces the risk of any damage or scratches to the actual lenses.
The lenses are perfectly protected under these filters as the dirt cannot penetrate to the actual lenses. It is recommended to keep this UV filters attached all the time for perfect protection. However it is important to have a good quality filter, otherwise it may degrade the picture quality of the photo. Since different lenses may have different filter diameters, you may have to purchase one for each of your lens.
2- Using lens hoods and lens caps:
The other important thing while using the camera is to use lens hood and lens caps for both front and back end of your lens. The lens hood and caps must be kept clean and shall always be attached to the lens.
3- Avoiding Dust
It is very important to not allow any dust to enter in the lens area. Dust inside your DSLR or film camera lens will attach to the back end element of your lens and also to the image sensor. While changing the lenses, the place should be dust and lint free. The position of the camera should be kept downwards so that dust is not allowed to get inside.
4- Using a Blower
Blowing the dust with the help of blowers is the most secured way to clean the lens and make it dust free. Blowers can be used directly aimed at the lens and also inside of your camera. As there is no direct contact to the lens of the camera it is the most secure way to clean the lenses, however it might not be able to clean the stains or settled dust on the lens.

