Get a tissue paper or a clean cloth. Damp it with liquid alcohol or water (alcohol is preferred). Take out the cartridge from the container and clean the bottom part.
Clean the nozzles using clean paper and the Clean Print Nozzles (or similar) command. This command come with the print driver and installs on the PC with the driver.
Typically, the software that comes with your printer has a utility that will clean these nozzles for you. I do not recommend that you try any other way to clean the nozzle.