Method and device for the operation of fuel cells

The method involves connecting a fuel-cell system to a component of a drive by a cooling and/or lubricating circuit that uses a water-based, oil-free coolant and lubricant. Contaminants in a fuel cell (20) of the fuel-cell system are detected. A flushing sequence is initiated to remove the contaminants using the water-based, oil-free coolant and lubricant, which contains water-soluble additives. The fuel-cell system is attached to auxiliary assemblies of a vehicle, where the fuel-cell system and the attached auxiliary assemblies have a shared cooling-lubricating circuit. An independent claim is also included for a device for operating a fuel-cell system.