I know I have posted some things about this before so ne need to remind me. But I was having trouble with ink tanks leaking and smudging edges of paper with black ink even with genuine Canon cartridges 210 and 211. I had the printer cleaned but never tried to empty the used ink like I read about. Today I was getting smudges and needed to print 25 sheets so I removed cartridges and cleaned them with Windex and a paper towel. I printed and the first two papers had a smudge at top left corner but rest were clean. And I believe I read somewhere you are supposed to use up the cartridges in I think 6 months or some number of months which gives me the idea even if full from seldom printing they need to be discarded or they may leak. What to others think of this idea? Any truth to it? Maybe the cartridges, even genuine Canon, go bad after some time and leak even if not empty. I just had that idea today and wondered if anyone else believes it or finds it true. Maybe I keep them too long because not that much to print.