subject: Tips to fill the cartridge for E-Cig [print this page] E-liquid is a liquid that has to be kept out of reach of children for the contents it holds. All cartridges are to be used within two weeks after refilling, and all cartridges have to be kept in a dry place. These precautions are important and if properly adopted, can be very beneficial as long you as wish to use the E-Cig.