Ink can dry inside the nozzle and clog an inkjet cartridge. You can clean away the clog with rubbing alcohol and a cotton swab. Remove the cartridge from your printer. Inspect the cartridge for signs of leaks. A cartridge covered in ink is probably empty, not clogged. If the cartridge is clean on the outside, dip a swab in alcohol. Gently rub the back edge and bottom of the cartridge to loosen the dried ink.