The leather your Charlie Noble is made from is incredibly robust. Cleaning is perhaps something that is given too much emphasis; any cleaning should be done only when necessary. It is not essential to the life of leather that it should be cleaned regularly, but at the same time an accumulation of dirt and grease over a period of time is undesirable and obviously, the longer it is left the more difficult it will be to remove.
Dirt is abrasive and over a period of time in extreme circumstances will cause the removal of the protective coating. Regular cleaning can be done simply by using a damp cloth, taking care not to soak the leather.
Use a cloth soaked in a mild soap/water solution (not detergent) and wring it
out until damp. Apply the cloth to the surface of the leather in a light
circular motion, turning the cloth regularly. Avoid aggressive rubbing action.
Repeat with a damp cloth rinsed in clean warm water.