If your camera lens has a filter thread on the lens (most do), buy a UV filter.
This has three main advantages – it will cut down haze in the distance on a bright day, it is easier and safer to clean than your lens, but more importantly, it will protect your lens.
It is much cheaper to replace a UV filter than your lens.
All my cameras and lenses are permanently fitted with UV filters.
If anybody has any questions about any area of photography, Pete will be pleased to answer them for you, just email email@example.com.