Birds are clean individuals. in the wild they root around in the diert etc but not in the small areas we make them live in. They live in a world washed by rain and disinfected by the sun. We should always try to give them a clean environment in captivity.
There are diseases which birds can carry which we can catch, like psittacosis and sometimes even Salmonella. Birds will sometimes also show disease due to these infections but they can be hidden and for this reason its important to clean and disinfect as a routine on a regular basis.
Have a look at our Ark-Klens which we recommend for daily/routine cleansing. Its been used everywhere including vets consulting tables, bird nurseries and is safe and non-scented.