The greatest enemy of hearing aids is water. Do not allow liquids to enter or contact the surface of the devices, including copious amounts of sweat. Do not use your hearing aids (except moisture-proof ones) while showering or bathing, visiting the swimming pool, etc. Dry the devices after each use. Use hearing dehumidifiers for it by removing the devices before going to bed. If you do not have dehumidifiers, open the battery compartment, remove the battery, and keep them that way overnight.