Electrical contacts, or terminals, in photographic equipment and on batteries must be kept clean to ensure that good electrical contact is maintained. Clearly there are two sides to the problem - the batteries and the terminals inside the equipment. Either of these can be the cause of significant problems.
Battery terminals should be clean on new cells but experience shows that this is not always the case. care should in any case be taken to avoid touching either of the two terminals as this leaves a greasy deposit which is then transferred in to the equipment. It is also worthwhile wiping battery terminals with a clean cloth or even on clean clothing prior to installation. Abrasive techniques should not be used unless desperate remedies are required. Many battery terminals have a protective coating to reduce oxidization and corrosion, and this is damaged or removed when abrasive cleaning is undertake. However, when all else fails out in the field, abrasive cleaning of the terminals may restore good electrical contact for a short period.
Electrical terminals within photographic equipment should never be cleaned in an abrasive manner because the removal of the protective coating will merely lead to corrosion and future problems. Terminals should be kept as clean and dry as possible, and should be cleaned in accordance with manufacturers' instructions. Internal battery compartment contacts can be difficult to access but, where possible, a specialized contact cleaner should be used to remove contamination. A clean cloth, such as a handkerchief, wrapped around the end of a pencil may be used to wipe inaccessible internal contacts. The rubber on the end of a pencil can also sometimes be used successfully to remove grease from inaccessible locations.
It is good practice to remove batteries from equipment which is not in use for some time. Leaking cells cause severe corrosion damage to electrical contacts. The only remedy may be to replace the relevant battery compartment.