We do not recommend using oil based lubricants such as WD40. For use with any type of cylinder lock due to their tendency to attract dirt and small particles, and eventually lead to sticking of pins and moving components.This small bottle, with it’s easy application nozzle, squirts graphite powder directly onto the key The key is then inserted and work backwards and forwards, giving long lasting, smooth lock operation.Prevents notchy, sticking action. Dry film does not attract dirt or grime.One small bottle will last for many applications